Questions on how often to change/clean filter

  • #1
Hello, I am new to fish keeping and I have been having a hard time with finding out the correct way to handle the filter on my tank, I get different answers at every pet store and just wanted to make sure I am not going to mess up.
I have a 20 gallon tank, it is an old one of my dad's form the 70's, but I have a new TopFin power filter with the cartridges that says it is for a 30 gallon tank. I have had my aquarium for about 5 months now, I cycled it for 1.5 months, and then added fish slowly, at 2-3 fish every 2 weeks until I got to 2 mollies, 4 danios, 2 platies, and one tiny little albino catfish like creature that I am not sure exactly what he is. All has been well as far as water parameters as of late. About 2 months ago, right after adding the mollies (which are the last fish I bought), I had a small nitrate spike but after biweekly water changes and more in depth gravel vacuuming, everything seems to be good. My question is, how often should I change the filter vance.cartridge and what is the correct way to do this? I bought replacement cartridges and have replaced it once, right after the whole nitrate issue 2 months ago, and I did it the way the petsmart guy told me to, which was to throw away the old cartridge, get the new one, put the carbon packet in it, run it under the faucet for 60 seconds, then just put it in the filter. That's what I did and I guess that is ok, but the more I read about the good bacteria and cycling the tank etc, the more worried I am that this is not the way I am suppose to be handling it and I don't want to harm my tank. I just got back from thanksgiving vacation to find that my black mollie was dead and one of my danios has completely disappeared, I can only assume dead and eaten. I had used those dissolvable topfin feeder discs while I was gone so I am not sure what happened to cause this. Before I touch the filter I want to make sure I do this correct. Thank you in advance.
20 gallon tank
30 gallon TopFin cartridge filter
1 air stone
plastic plants
gravel, about 2.5 inches deep
water temp: 78 degrees, Fahrenheit
Nitrate: 15-20
Nitrite: 0
pH: 7.0
KH: 40
GH: 120
(I know my GH is high, the petsmart guy told me to sprinkle aquarium salts about 1 tablespoon a week to help, and it has taken it down from 180 to 140, but very gradually).
The fish I have at present: 3 danios, 2 platies, 1 mollie, and 1 tiny little catfish like fellow.
all of these fish seem to be doing well, active, swimming all over tank, etc. The danio that disappeared on me had previously been swimming really weird, almost like his back was bent like he was kyphotic or something which was weird, but maybe that means he was already unhealthy? The mollie's death was a surprise though, previous to my 4 day vacation he had seemed fine. He was never super active but I was told most mollies aren't? Thanks, and sorry for the long post, I just didn't want to leave anything out. But my main question is about the filter, how is the best way to change it? thanks!
  • #2
watch how much salt you put in as this could damage the equipment you have, or just cause some corrosion.
As for changing the filter media...... What I do for my 120 is every 3 months I rinse out the filter media cartridge with some tank water ( put into a bucket ) so about 6 months in I change the filter media ( after keeping the old filter media in the tank for about a week so it can mature alittle bit before taking the old catridge out and tossing it )
  • Thread Starter
  • #3
Thank you! That makes sense Ok, I will lay off the salt for a while then, as I been using it for a couple of months now, I hope I haven't messed anything up too bad. I was just worried about the GH, but I will just keep an eye on everyone and hopefully that won't be an issue. Thanks!
  • #4
Haha, the guy at the store didn't know what he was talking about. I imagine the deaths were from the lacking bacteria.

Depending on how often you feed and other factors, waste buildup in the filter may cause the filter output to slow down. Once I notice it isn't working as well, I squish out the gunk in a bucket of old tank water and put it back into the tank. I've actually never replaced my sponges, haha (a couple years).

Also, the little catfish thing is a corydora, corie for short. You should have at least 3-4 of them, since they like to be in schools. I wouldn't get more right now with the bacteria issues, but in a couple weeks I would consider adding a couple to keep the lone one company.

This is my favorite food for my cories, they really like them! They need protein, don't feed them algae wafers.
  • Thread Starter
  • #5
Oh wow, thanks! I didn't know what my little guy was (I call him Sam Elliot since he has a white stash lol), I will have to get him some company in the near future. I had also wanted to get my Danios more company since I am down to 3 of them and I read they like groups of 6 but I didn't want to overstock my tank either. I will definitely look into some company cories as well as that food for him, I had just been feeding him the flakes I was feeding the others. Thank you! And thanks for the filter advice too. I will start cleaning my filter out as you all have suggested. I had a feeling, based on other threads I have been reading, that maybe I wasn't doing it right so I really appreciate the help
  • #6
For your 20G tank, if you want as your other mollies and danios die you can try going for barbs or going for some loaches, fun fish to look at and watch eat. you could do a puffer ( a pike puffer gets only about 2Inches )
  • #7
Wow, a 40-year-old tank. That's why I don't like throwing stuff away either!

I also started out by throwing away the filter pad every 4-12 weeks. The reason I might go longer was I always tried to stretch the filter pad also. However, I have since learned that you really don't need to replace the filter pad very often at all. The main reason why it is suggested to replace every 2-4 weeks is because of the activated carbon that is inside these filters, which does expire.

However, if you don't mind running the tank without carbon, which you can certainly do, then the plastic grid and blue filter material would last a really long time. So recently, I have just cut the filter and removed the old carbon. By not replacing the entire filter pad, then you can keep the bacteria that have been growing on there.
  • Thread Starter
  • #8
Thanks! Yeah it is an awesome tank, my dad loves fish and when I got a betta tank, just a little one, my dad said he wanted to share his passion and gave me his very first tank, complete with 70's wood paneling lol. I love it.
  • #9
For the corydoras it may be better to keep them in a group of 6 or more because they are much more at ease that way
  • #10
Your gh is just fine, but your kh is a little low. I would recommend that you add some decorative shells, corals, decorative aragonite rock, decorative Texas holey rock, or add some crushed coral, crushed oyster shells to the tank to bring up the kh. KH controls your ph, and if you loose much more, your ph could drop. GH, I suggest you stop messing with. The gh is needed for the osmotic process of fish. Mollies like a little higher gh as well.

You missing something vital on your strips. You need an ammonia test badly. Ammonia processing is the first step of a cycle. With out that info, plus you changed the cartridge, you could have high ammonia and not know it. Please pick up the API Master Test Kit instead of using the strips. As soon as the strips are exposed to the air the activate, which causes inaccurate reading. Keep the strips for the kh and gh, but get the test kit for the rest.
  • Thread Starter
  • #11
Oh yikes, thank you for all of your information! I didn't realize all of that. Ok, I will stop at petsmart tomorrow and get the master test kit and also some coral or oyster shells. Thank you so much for your input. I have a danio that is acting funny today, the same way my other one did before he disappeared. It's almost like the back half of his back is bent down in a slump. He is still eating and swimming ok but that is weird and it's what my other guy started doing. I will post the best pic I can get of him. Do you think it's related to my water being messed up?
  • Thread Starter
  • #13
He was at the surface because I tricked him with my finger to get the pic, but he swims all over the tank but he has started holding his back down like that, or even usually even more bent but I can't get a pic that shows that
  • #15
mmm, yeah, that's not a great sign. I've only had that once with my fish, but he didn't make it... I know it's a reaction to the water, kind of a weird reaction though. Must be some parasite or something.

Here's a post I found relevant.
  • #16
Arched back is a symptom of many things. From a vitamin deficiency to TB, and several things in-between like parasites, bacterial infection, etc. It would be hard to say what exactly is the problem given the fact the arched back is the only symptom, and it's eating and swimming are normal. If I may suggest, try this link, and mark every symptom you see, and see what it says.

If I had to guess personally, I would guess a vitamin deficiency due to the fact you have been messing with your gh by adding salt. I would suggest a 50% water change to reduce the salt in the tank and to increase the gh. Moniter the fish for 24 hours. If no improvement, do another 50% water change, and moniter. If still no improvement, we will have to look at other things.

Also when you do get your test kit, please test both tank and tap water and post the results. Also please read the instructions carefully for the test kit. Nitrate bottle #2 is a finicky bottle, and I even pound it on my hand or desk for 30+ seconds before adding the drops to the tube. Follow them closely when it comes to the nitrate test. Failure to do it right will give you a bad reading.
  • #17
within the arched back, most causes are because of the Vitamin deficiency within the tank. so following what Dragon said, do 50% water change, as this will help stabilize the tank parameters of Gh and Kh, then just watch it if it dies, then the aquarium salt may of been the culprit of this fishes pain and suffering.
  • Thread Starter
  • #18
Thank you. I am so mad at myself for just listening to the petsmart aquarium guy and not doing more research on my own I wish I had discovered this forum before getting my tank going at all, would have gone much smoother! Thank you all for all of your help. I am doing a 50% change tonight then buying the correct test kit tomorrow and going from there. Of course this is happening at the same time I am studying for finals!
  • #19
hah, finals... Same here. the stress is real.
  • #20
Please don't beat yourself up for PetSmart misinforming you. We all have been trapped in their supposed "Fish Specialist" misinformation from many different places. Not many shops really educate their staff on aquarium care, and the info they give them is like 20 years old, like a Betta can live in a bowl. So what information you got isn't uncommon at all.

Here is a basic list of things to keep in your fish bag at all times. Shells or crushed coral, Seachem Prime, API Master Test Kit, and for those rare occasions that the bio filtration hiccups, Seachem Stability, and a syphon vacuum for tank maintenance. Gravel vacuuming is really important to do, because food and fish waste can be hidding in the cracks between the rocks, and messing with your water quality.

I'm sorry for back tracking, the squirrel just jumped from the wheel in my brain. Can you use a strip and also test the kh and gh of your tap water? Also post the ph on the strip as well. My gut is telling me to have you check other issues, so before I derailed that train of thought, I thought I should add it.
max h
  • #21
70's wood paneling, you're making me feel old, both my55 and 110 have the simulated wood frames. Then again they where cheap.
  • #22
I wouldn't be too hard on yourself. How are beginners supposed to know what to do when people at pet stores tell you the wrong thing?

As others have said, don't ever throw away the cartridges. THat is where your bacteria grows. If it gets clogged just take it and clean it out in some dirty aquarium water then put it back in.

I actually don't use the cartridges at all in my HOB filters. I usually get a media bag (can be bought cheaply at petsmart or petco) and fill it with biomax or matrix biomedia then shove it down into the filter. I then use a prefilter sponge on the intake to filter out the junk. Now, by no means do you have to do it this way, using the cartridges will be fine.

I also agree with the others, once you get your levels in line, the danios and corys could use some company. Is this a 20 long or 20 high? How long is the tank?

What part of Tennessee?
  • Thread Starter
  • #23
Ok, I got the API master test kit and tested tank water as well as my tap water. Results:
Tap water:
Ammonia: 0 Nitrite: 0
Nitrate: 0 pH: 6.8 KH: 40
GH: 60
Ammonia: 0 Nitrite: 0
Nitrate: 20 GH: 180
pH: 7.2-7.6 (between) KH: 40
  • Thread Starter
  • #24
And my danio's back is still crooked but he is swimming and eating fine, that diagnostic test I took for him says it could just be congenital. He is a youngster so maybe he just has scoliosis? Guess I'll just keep watching him? Maybe little Phil Fulmer just has a wonky back hopefully? Oh, my tank is 24" long and 14" high. Not sure how many more cories or Danios I should add to the tank but I do feel bad them not having enough friends. tyguy7760, I'm in the tricities region of Tennessee.
  • #25
Ok, you have a slight variation between tap and tank in gh and ph. Something in your tank is increasing your gh. Do you have any decorative rock pieces in your tank? I'm also counting rocks with fake plants glued to them. Has any paint chipped off in your gravel? Anything loosing it's paint off if it?

The ph looks good, but I'm wondering if you have Co2 added to your water. Can you test something for me. Can you fill a clean jar or glass full of water. Test the ph, and write it down. Then if you have an extra air pump, aerate the water for about an hour, and test the ph again. Write down the results. Then test again at the 12 and 24 hour marks. Then post the results. If you do not have an extra pump and stones, please just test at the 12 and 24 hour mark and post the results.

I'm very happy to see ammonia isn't the issue with your tank. I was afraid the arched back was due to ammonia poisoning.

The kh still has me worried. I would like to see it between 80 and 120. Did you by any chance get shells or crushed coral?

How is the fish doing after the water change last night? Please let us know.

Edit:. Just saw your answer. That sure could be it. As long as no one else start to show the symptom, I would chalk it up to a genitive defect.
  • Thread Starter
  • #26
I couldn't find any shells or coral/crushed coral at petsmart today, I may have to order it online. There aren't really any other pet stores local. As to the paint, I don't see anything but there could definitely be some chipping off because I have that glow fish gravel that is black with the random pink, green, blue rocks in there and also my little deep sea diver dude that the air stone is hooked into is also painted. So I wouldn't be surprised if some is chipping off. Do I need to get that stuff out of there? I hadn't thought of decorations they sold at petsmart as being unsafe but now I'm not quite so trusting of petsmart haha. I don't have any other air stones, but I have set a cup of water from the tap out and will be timing it. Right now it's pH is 6.8.
  • #27
No, nothing wrong. They are safe. I'm just trying to figure out why your gh jumped from 60 from the tap to 180 in the tank. Normal cause for an increase is rock erosion, such as people that have natural wells that is deep enough to be in limestone. Ceramic decorations that are only painted or glazed on the out side can do it too. Also paint coming off of gravel can as well. Unfortunately it's not the right minerals that they are releasing. So you might want to consider the coral or aragonite, Texas holey rock, or limestone to your tank. Otherwise I suggest maybe a vitamin supplement for fish, since your gh from the tap is so low.

The only other possibility is rain. If you have had a lot of rain in the past couple of days, that can change your tap water peramaters. I know I experience it here in Missouri. When we have a lot of rain, or rain up north where we can teach flood stage, my kh and gh drops out. When we have had little rain, my gh sky rockets to almost 200, but my city keeps the kh low to prevent build up in the city pipes. So maybe you got older water when your gh was up, and if it rained recently, it could of dropped it.

Just guessing right now on the cause of the huge difference in gh.

Sometimes in the Betta section so Petco and Petsmart you can find crushed shells sold as substrate for Betta tanks/bowls. Those will work. Also the hermit crab feeding shells will work too as long as they are not glazed or painted. In the salt water section is where you can find the crushed coral and aragonite sand, but they normally come in 8 to 20 pound bag. Granted you will only need about a cup of it, so it's your choice if you want to spend on it. In the bird section is where you can find crushed oyster shells, and even a bird cuttlebone will work, but the cuttlebone won't help with gh, and does not last long because they get a film on them and stop dissolving. If you know someone that raises chickens, they might have crushed oyster shells as well.
  • Thread Starter
  • #28
Oh thank you so much! I appreciate all of your help and also letting me know where to find everything! Thanks! Well, that is interesting about the rain, where I am in Tennessee it has been terribly dry (we have been having terrible fires and smoke etc everywhere) and yesterday and today were the first days in weeks it has rained at all. That is something I hadn't considered at all. When I get the crushed shells tomorrow, do I add them to the filter or just sprinkle them in the gravel?
  • #29
Cories in a 20G tank can hold a group of atleast 6. Danios can have a group of atleast 7-10 if you wish
  • #30
Well, that is completely up to you. Giving that your gravel is black, I doubt you would like the snow effect messing with the look of your tank. If your fine with that look, you can sprinkle it through out your tank. Otherwise, I would get a media bag (found in the filter section), or an unused knee high stocking and add about a cup of it, and put it in the filter. Make sure you rinse the shells well to get the dust off, or you will cloud your tank. Also, you will notice that your ph will rise a bit using it. Not much though. Maybe a point or two. If your still unable to find what your looking for in the amount you want, then please purchase a small plain bird cuttlebone. Break off a piece and toss it in the filter. That will work in the meantime to keep your kh from dropping lower. Then you will have some time to locate and order what exactly you would want.

Sorry to read that your close to the fires. Hope you and your family stays safe and the winds blow in your favor.
  • Thread Starter
  • #31
Thank you, so far all we are getting is a lot of smoke where I am, but I know others have really lost a lot in the fires. Just praying for some really good rain soon.
Ok, my tap water I had set out was still pH of 6.8 this morning and had risen to 7 this afternoon. Is it normal to rise like that? I got crushed coral and put it in a media bag in the filter. Hopefully that will help. I'll recheck the KH and GH in the morning once it's had a chance to work. Bad news on little danio though. He is still alive but he is definitely not ok. He is just hanging out by himself in the top corner of the tank and barely swimming and he wouldn't eat. Something is wrong with him but I don't know what
  • #32
It just means your water company puts in some Co2 in your water. Not a lot if your ph only went up .2. It might be a little more then that, but it usually takes only 24 hours for a complete gas off. Aerating just makes it go faster.

Sorry to read about the fish. Now that he's stopped eating and became lethargic, I'm sorry to say his survival rate is really low. Your the first person I'm saying this to, but maybe euthenasia is required. Main reason is we do not know the root cause. Plus since you do not have a quarantine tank, what ever he has could pass to the other fish. Especially if he passes and your not home to remove him, and the other fish gets nibbles in. Though I still think it's a vitamin deficiency, it still could be other things. The most humane way I've found is the use of clove oil. Just get a small glass cup, put tank water in it, place the fish in, and then drop a single drop of clove oil in the cup. With in seconds, the fish will fall asleep and be numb. Add another drop, and with in a minute the fish will pass. If you want to make sure, add a second drop at the end and wait another minute.

Again we do not know the root cause for his problems. It could be genetic and it's just his time. Could be vitamin deficiency, and we didn't get to it soon enough. Could be a parasite. Could be bacterial. Could be a disease like TB or NTD. Several bacterial and parasitic show the same symptoms, so to rule out all but one would be hard. To be honest, that is the only recourse I can truely see. Sorry. I'm so sorry to say it too.
  • Thread Starter
  • #33
Thank you for your honest and fast response. I do hate to do that but I also do not want whatever he has to infect anyone else. I agree with you and will go ahead and take care of it. He has gone downhill fast in a short amount of time.
  • #34
Keep and eye on the others in the tank as well. If you see one break away and stop eating, we have bigger problems. What ever it is spread. Then it's fining the problem, which isn't easy. Let's hope the coral brings up the minerals in the tank, and reduces the mineral deficiency. You still may want to consider a vitamin supplement to help boost your other fish immune systems. Like Vita-Chem, and you can even use infant vitamins, as long as there is no high amount of preservatives. Vitamin D is the biggest one that is needed. Vitamin B complex is next. If you can not get Vita-Chem for fresh water fish, consider the infant vitamins.

lol Sounds weird to recommend vitamins for fish doesn't it? But if you consider they live in a closed environment with out their natural resources, plus what ever food we feed them, deficiencies is bound to happen. That is at least my opinion.
  • Thread Starter
  • #35
Oh no, I hope it doesn't spread. Ok, yes I will go on a vitamin search tomorrow and hopefully everyone else stays healthy. Thank you so much for your help again.
  • #36
Your very welcome. Please post the results of your kh and gh test tomorrow. I don't expect much movement in ph, but your kh should raise a bit. Also retest your cup of water tomorrow morning and post that was well.

I'll be monitoring your thread, so if you think of something, please don't hesitate to ask. Plus if I don't know, there is a lot in here that will. lol

Similar Aquarium Threads

  • Locked
Top Bottom