Ph Swings, High Nitrate, Low Kh

Hi. So, my pH keeps swinging from 7.4-7.9 and back. I think it's caused by low KH. I've been bad about water testing in the last few weeks (would've been doing better if I had noticed pH swings, but I didn't look back at all the results until yesterday) except that I've been better about it the last few days, but still, the results probably don't really show everything that's happening. But here are the results from the last few weeks, copy-and-pasted from my list of the results of every water test I've ever done for my fish:

5/24/17
1. Nitrate 7.5 ppm
2. Nitrite 0 ppm
3. Ammonia .125
4. High Range pH 7.4
5. pH 7.4
6. GH 5-6 drops, 83.3334-100 ppm
7. KH 4 drops, 66.6666 ppm

6/3/17
Numbers go left to right
1. Ammonia 0
2. High Range pH 7.9
3. GH 6 drops
4. KH 4-5 drops

6/12/17
Numbers go left to right
1. Nitrate 30 ppm (a little high)
2. Nitrite 0 ppm (good)

6/16/17
1. Nitrate 30 ppm
2. Nitrite 0 ppm
3. Ammonia 0
4. High range pH 7.4
5. pH 7.4
6. GH 6-7 drops, 100-120 ppm
7. KH 4 drops, 66.6666 ppm

Lol "Numbers go left to right" is just there to remind me which test tube has which test chemicals, in case you're wondering. When I see that, I know the first one on the left has nitrate stuff, second is for nitrite, third is for ammonia, etc. Sometimes I remember to put that there, sometimes no.

What's the safest way to fix the pH and KH issues? I've heard of something involving crushed coral, but how do I do that method? Also, where's the best place to buy crushed coral? Is there a best brand?

I know my nitrate is a little high, but I didn't want to do a water change to try to fix it, because I was afraid it would affect the pH and make it swing. Is a water change a safe way to try to fix the nitrate problem? What are some other safe ways, just in case that one's not safe or doesn't fix the problem? I was keeping it in check with Tetra EasyBalance Plus, which was also keeping the pH at 7.9-8.0, but then I kept hearing that pH balance chemicals were bad, so I stopped using it.

I hope a water change is safe. My water level is low.

I have a 5.5-gallon tank, 3 male guppies, and Cryptocoryne WendtiI that may have some algae on it.

 

NitrAtes are probably fine some fish are more sensitive but if you are changing at 40 most fish don't suffer ill effects. Change water to remove them is the best and most reliable method.

Crushed coral, you can buy it as a substrate and use a stocking or filter bag to add some to your filter. Your kH is low but it's still there I didn't see what size your tank was but so long as it's 20 or larger I'd start with about a quarter of a cup per 20 gallons and test daily at least kH and gH if it starts climbing over 10 remove some of the coral. Personally I remove half if kH starts dropping add half of what you removed back if it starts getting too high again remove a bit. It's easier to dial in than way and by no means do you have to weigh and measure precisely. And unless you are up near 100 gallons you should have it dialed in within a week. Obviously if your kH isn't changing add a bit more until you nudge it up.

PH balancing through chemicals in my opinion is a recipe for disaster. Best to resolve the issue and monitor at water changes so you know when to toss and refill your coral bag.

I see tank is 5.5... I'd add two tablespoons of coral and then add/remove again as necessary testing every 24 hours for sure. Small tanks have a tendency to make sudden dramatic changes

 

NitrAtes are probably fine some fish are more sensitive but if you are changing at 40 most fish don't suffer ill effects. Change water to remove them is the best and most reliable method.

Crushed coral, you can buy it as a substrate and use a stocking or filter bag to add some to your filter. Your kH is low but it's still there I didn't see what size your tank was but so long as it's 20 or larger I'd start with about a quarter of a cup per 20 gallons and test daily at least kH and gH if it starts climbing over 10 remove some of the coral. Personally I remove half if kH starts dropping add half of what you removed back if it starts getting too high again remove a bit. It's easier to dial in than way and by no means do you have to weigh and measure precisely. And unless you are up near 100 gallons you should have it dialed in within a week. Obviously if your kH isn't changing add a bit more until you nudge it up.

PH balancing through chemicals in my opinion is a recipe for disaster. Best to resolve the issue and monitor at water changes so you know when to toss and refill your coral bag.

Should I leave it in the filter bag permanently when I put it in the filter? And when I replace the coral, do I need a new filter bag or do I just empty the old one and put the new coral in?

 

Media bags can be reused until they are worn out. And the coral may last a long time.

 

Should I leave it in the filter bag permanently when I put it in the filter? And when I replace the coral, do I need a new filter bag or do I just empty the old one and put the new coral in?

You don't have to use a bag, it's just much easier to keep clean and change etc in a bag rather than loose. You can use the bag until it falls apart no reason to change it till it can't hold together anymore.

 

For how many days should I test every 24 hours?

 

I would test daily until it's stable and unchanged for at least 5 days. After that weekly during regular tank maintenance.

 

All good advice. I just wanted to add that depending on how large your tank is, will dictate how often you need to add more coral. I have a 30 gallon tank, with about a cup or so of crushed coral in my filter. I need to add more about every 3 weeks. It does get used up, but not 100%, so I do have to dump half the bag out from time to time to make room for more. I have a large hob filter so the basket does accommodate a lot of media though.

My signal to add more is if my pH drops at all. I stay steady at 7.6 all the time. So if I drop to 7.2 then I know it is time to add more coral. Now that I am stable I only check my kH/gh once a month. Just to keep on top of it.