How often do I really need to change water?

[MMac]

Sorry if this post is in the wrong spot.

Since I cannot seem to give my tank away...I guess I will keep it.
So, I have a question - please allow me to reason this out and please tell me if I am off base.

tank: 50 gal (48x18x15 - lwh)

panda cories
oto cats
ember tetras
Siamese algae eaters
Amano shrimp
neocardina shrimp
assassin snail

Bacopa
vals
monte carlo
java fern
...and the dreaded bba (controlled through husbandry)

Fluval 307 canister & aqua clear 30 HOB (polishing media only)
RO Water & CO2 injection

My understanding is that water changes are designed to keep the water parameters under control. Today marks two weeks since my last water change. Tested (API master test kit) the water and found the following:

0 Ammonia
0 Nitrites
~ 5 ppm Nitrates
TDS @ 174

That looks pretty good to me. I usually have to add a gallon of water every couple of days due to evaporation. I top off with RO water - my tap water is super hard.

My thought is that with those parameters I don't need to change the water (trying to lessen time spent on fish b/c of other factors in my life). Also, will shoot to keep TDS </= @ 200. Also, when I do a w/c I will use RO water and add 1/4 tap water per gal to reconstitute minerals.
To be honest, with the extended w/c timing my tank looks better - the bba looks like it is dwindling and my plants are super healthy and growing like weeds. I have to prune everything every week as well as sucking up bba balls that have attached to sand. The java fern is a bba magnet so I just pull off infected areas and it is also looking pretty good.

Thoughts? Is my reasoning flawed?

My thought is that if I test each week and I get those types of parameters, I should be good to go another week.

Do I need to worry about minerals?

I use thrive shrimp friendly fertilizer in the water column and thrive tablets under the vals.

All input is appreciated.

Thanks!

 

[Blobbyfish123]

I’m no expert but I think you are supposed to do weekly water changes just to make sure it stays clean and properly maintained

 

[MMac]

I’m no expert but I think you are supposed to do weekly water changes just to make sure it stays clean and properly maintained

Yes, but I think "clean" refers to the water parameters that I listed above which are stable and well within the parameters to be considered clean. I do remove algae as needed, I prune plants, etc. The weekly w/c is what I am trying to gauge as to if they are really necessary with the water parameters I posted as long as those water parameters are stable.

Thanks.

 

[Kwikfab]

Minerals are replenished with water changes

Minerals that are otherwise consumed during the natural cycling process

You also have other dissolved goods in your current water; water changes bring fresh water

 

[cdr63corv]

Well if your plants are healthy and by your testing results, guess I'd try 3 weeks between water changes and see what it tests at. You didn't mention how many fish you have. Kaveman aquatics had some videos on water changes on you tube you might find some answers. Good luck

 

[MMac]

Well if your plants are healthy and by your testing results, guess I'd try 3 weeks between water changes and see what it tests at. You didn't mention how many fish you have. Kaveman aquatics had some videos on water changes on you tube you might find some answers. Good luck

I have about 12 panda cories
2 oto cats
3 siamese algae eaters
8 ember tetras
7 amano shrimp
1 assassin snail
numerous neocardina shrimp

Thanks for the video suggestion.

 

[Leeman75]

Given that you have shrimp, I'd say that the mineral depletion is as much a consideration as your nitrates. The shrimp need the calcium and minerals for their shells.

 

[Fishfur]

Water changes remove more than nitrates. They also remove dissolved organic compounds and hormonal secretions from aquatic life.

It is possible to reduce the number of changes but supplementing minerals on a constant basis works better than dosing them does.

Wondershells are one way to do this. But water changes can’t be eliminated in a small closed system like a fish tank,

 

[MMac]

Water changes remove more than nitrates. They also remove dissolved organic compounds and hormonal secretions from aquatic life.

It is possible to reduce the number of changes but supplementing minerals on a constant basis works better than dosing them does.

Wondershells are one way to do this. But water changes can’t be eliminated in a small closed system like a fish tank,

Thanks. Makes sense.

Given that you have shrimp, I'd say that the mineral depletion is as much a consideration as your nitrates. The shrimp need the calcium and minerals for their shells.

Thanks!

 

[Mudminnow]

CO2 injection

CO2 injection causes plants to grow much faster. Therefore, plants in such tanks will need to be fertilized much more to keep up with all that growth (especially if lighting is high). With all that fertilization, there's bound to be something that gets added at a rate higher than the plants consume it. Water changes make sure those left-over fertilizers don't build up too much.

My understanding is that water changes are designed to keep the water parameters under control.

Yep. Water changes keep stuff that could become harmful from building up too much, and they can replenish other things that get depleted.

0 Ammonia
0 Nitrites
~ 5 ppm Nitrates
TDS @ 174

That looks pretty good to me.

Looks good to me too.

My thought is that with those parameters I don't need to change the water (trying to lessen time spent on fish b/c of other factors in my life). Also, will shoot to keep TDS </= @ 200. Also, when I do a w/c I will use RO water and add 1/4 tap water per gal to reconstitute minerals.

Seems reasonable.

To be honest, with the extended w/c timing my tank looks better - the bba looks like it is dwindling and my plants are super healthy and growing like weeds.

It's interesting to me that you're seeing this in a tank where you add CO2. Holding back on water changes often has this effect on low-tech planted tanks, because water changes can cause CO2 instability in such tanks. I wouldn't think your tank would see the same effect.

Perhaps your plants were nitrate or phosphate limited and your water changes were stripping this from the water.

Thoughts? Is my reasoning flawed?

CO2 injection makes your plants grow 10-20 times faster. This fast growth means more trimming, more fertilization, and more water changes. So, if you're really aiming for a low maintenance tank, I'd recommend ditching the CO2 and going fully low-tech. A low-light, low-tech planted tank can go months (or more) without the need for water changes.

My thought is that if I test each week and I get those types of parameters, I should be good to go another week.

Agreed.

Do I need to worry about minerals?

Yes. You won't want to run out or build up too many.

 

[MMac]

CO2 injection causes plants to grow much faster. Therefore, plants in such tanks will need to be fertilized much more to keep up with all that growth (especially if lighting is high). With all that fertilization, there's bound to be something that gets added at a rate higher than the plants consume it. Water changes make sure those left-over fertilizers don't build up too much.

Yep. Water changes keep stuff that could become harmful from building up too much, and they can replenish other things that get depleted.

Looks good to me too.

Seems reasonable.

It's interesting to me that you're seeing this in a tank where you add CO2. Holding back on water changes often has this effect on low-tech planted tanks, because water changes can cause CO2 instability in such tanks. I wouldn't think your tank would see the same effect.

Perhaps your plants were nitrate or phosphate limited and your water changes were stripping this from the water.

CO2 injection makes your plants grow 10-20 times faster. This fast growth means more trimming, more fertilization, and more water changes. So, if you're really aiming for a low maintenance tank, I'd recommend ditching the CO2 and going fully low-tech. A low-light, low-tech planted tank can go months (or more) without the need for water changes.


Agreed.

Yes. You won't want to run out or build up too many.

Thank you for the detailed information. I will test the phosphate levels and see what they say. Since cycling the tank almost 2 years ago it has always run low on nitrates. Usually around 5ppm, max has never been over 10ppm when tested after cycling.

CO2 injection causes plants to grow much faster. Therefore, plants in such tanks will need to be fertilized much more to keep up with all that growth (especially if lighting is high). With all that fertilization, there's bound to be something that gets added at a rate higher than the plants consume it. Water changes make sure those left-over fertilizers don't build up too much.

Yep. Water changes keep stuff that could become harmful from building up too much, and they can replenish other things that get depleted.

Looks good to me too.

Seems reasonable.

It's interesting to me that you're seeing this in a tank where you add CO2. Holding back on water changes often has this effect on low-tech planted tanks, because water changes can cause CO2 instability in such tanks. I wouldn't think your tank would see the same effect.

Perhaps your plants were nitrate or phosphate limited and your water changes were stripping this from the water.

CO2 injection makes your plants grow 10-20 times faster. This fast growth means more trimming, more fertilization, and more water changes. So, if you're really aiming for a low maintenance tank, I'd recommend ditching the CO2 and going fully low-tech. A low-light, low-tech planted tank can go months (or more) without the need for water changes.


Agreed.

Yes. You won't want to run out or build up too many.

 

[Marlene327]

I'm at 3 weeks now in my 40 and a 10 gallon. Most of all I'd like to get that 10 changed out, but maybe tonight. I'm so busy every day, time is flying by and they're lucky to get fed. I've even forgotten that twice in the last couple months. I hit my pillow at night and am OUT! I wake up in the middle of the night feeling bad, so they got a morning feeding instead of evening. I'm sure my perimeters are good, I'm not overfeeding and everything is healthy. My vals are taking over, it's crazy how much they can grow in 2-3 weeks! I've been cutting 6-10" of them down every cleaning. I see they're spreading to places I don't want them, and algae is starting to cloud the glass. Did I say 3 weeks? Maybe it's been 4... I need to put it on a calendar. The point is, if the filters are all working, your animals are healthy, the water is clear with no bad smells, I don't think we're hurting them. I'm now motivated to get in there this evening and get it done after dinner!

Everyone's tank is different. There are "rules" for everything. But after having this tank for 6 or 7 years, I feel like I know it pretty well. I can tell when my fish aren't happy, and that's a scary sign to get busy. I think if you're checking your levels so well and all is good, then you're doing something right. My nitrates sneak up to 40 and never ever go lower than 20, even with a 75% WC - it's just how it is and 40 won't kill anything. I do 50-60% every change, clean glass, filters, cut plants back, and am astounded with my gorgeous tank when I'm done! I never see it getting dull, except for the vals floating on top. I cut them down 3" below the water line every time and like them THERE!

Take care of your tank the way YOU need to, for your satisfaction and your fish's health. I get so tired of rules and guilt. There's so much more of life to deal with. I love my fish more than ever since I got rainbows, really enjoy them alot. Also enjoy my shrimp that I mixed together. Used to have 2 tanks and don't have time for that. Some went into 1 tank, and a lot of culls went into the larger tank. They're either living in the plants or became fish food. I can't see through the jungle but have seen some on a sponge filter in the back, so they're around!

I will add that I use well water, and it's HARD water, lots of minerals. Have only used RO when my shrimp had trouble when I was starting out with them. Richie guided me on that, and I sure miss that man being here! That's expensive to buy, and I also used some distilled. But all good now.

 

[kansas]

The problem is that you learn you are not doing enough water changes when disease breaks out in your tank.

I do one every 7-10 days. it takes an hour and a half for two tanks.

 

[Marlene327]

The problem is that you learn you are not doing enough water changes when disease breaks out in your tank.

I do one every 7-10 days. it takes an hour and a half for two tanks.

And you're doing what's right, we're told that's how to keep our fish healthy. Every tank is like every person - each is unique in its needs. Breaking out with ich or any other weird thing is terrifying, and I'm betting every aquarist has had to deal with it once or twice. I bought too many fish almost 2 years ago and had a terrible ammonia spike that wiped out half my tank. What a rookie mistake that was, I was so mad at myself. They were fine one day, dead the next, and the next, and wow was I changing water. I never measured the level, I just knew. So although I'm dying to add a few more, I'm restraining myself, won't do that again!

 

[MMac]

Today is week 3 w/out a water change. Parameters still look good - 0 ammonia, 0 nitrites, 5-10 nitrates. I forgot to take tds reading before changing the water, but after adding about 3 gal of ro water, laced with 1 cup tap water, the tds was 157.

While the parameters look great, I see the wisdom in the posts about the mineral depletion, so I will continue with 7-10 day w/c intervals. I think my tank inhabitants are happy with that and I do love a sparkling tank!

Thanks!