GH, KH, PH Confused Beyond

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koigal

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Oct 13, 2019
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Hi, I am so confused with what to do it is driving me obsessed. I'm also not sure if this is in the right section.
I have a 40gal. tank with koi fry that had to bring in for the winter. It took 7 weeks to cycle. Now my KH is low and PH is at 6.8-7.0. I would like it higher, usually when I do a water change it will bring it to 7.4 and hold for the week. The day after the water change- it was 6.8-7.0 and the KH was 0. Gh is 5 drops. I have a live rock in there, but it obviously is not doing much anymore. I have researched so much that I can't even comprehend what I read anymore. Everyone keeps telling me if I don't get my KH up, my fish will die. I had an old buffer that I put 1/4 tsp in a bucket of 2 gals. It brought the PH to over 8 and the KH to 5 drops. I am scared to add that to my tank as it is a HUGE difference. Can I put that 2 gals in slow over the day and will it even do anything? I don't want to have PH go up fast and then back down again.

My tap water is GH 2-3 drops, KH 2 drops and PH 7.8-8.0
Why is the tank GH higher than the tap GH? Is that enough minerals for their gill function?

During a search, I saw something called Calcium Reactor Media. Is this something that could keep KH and PH at a good range on a stable basis? Can it be used with only sponge filters and a bare bottom?

Any help would be greatly appreciated as I don't want to kill my fry or stress them anymore than the cycle did.

tank 10-4.jpg
 

FreshyFresh

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I would let a sample of tap water sit overnight and then test it.
 
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koigal

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Please start by going here: http://fins.actwin.com/mirror/begin-chem.html

After you have read both sections, come back and ask your questions.
Thank you for that information. Some I knew-and just try to figure out how to fix my water situation for my fry. I tested my tap after it sat the night and day. The lighter one in the photo is the tank.
I also tested my other parameters and attached those as well. Is that PH 7.0 or 6.8? I can't tell when they are close.
I have been adding some each night of the buffered water, but after I put it in, they seem to shimmy a bit. I am adding it half and half with tank water and putting it in like that. But at 4 cups a night, it's not raising the PH. I wish my town didn't have soft water. Could I add clay with calcium that is for ponds?tap & tank 10-15.jpgtank 10-15-1.jpgtank 10-15-2.jpg
 

the loach

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Aug 6, 2018
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People are scaring you... a pH of 6,8 or 7 is just fine for koi. You don't have to change it.
Large pH changes aren't good for any fish. Just keep the water stable, and without ammonia (is that 0,25 I see there, it should be 0 (yellow) at all times, though it might be a false reading)
The danger with a low KH is that pH easily changes. You could get a pH crash but with a lightly stocked tank, regular water changes and monitoring of the water quality a low KH isn't a problem. Your fry is fine for now, it depends on how many there are, the temperature and until which size they have to stay there before it gets more complicated....
 
Apr 2, 2002
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Your test results look OK to me. But colors are somewhat subjective. Here is what I see.

pH is in the 7 to 7.2 tange.
Ammonia is 0.
Nitrite is 0.
Nitrate is in the 5 ppm range. This test is the least accurate of them and is especially so in the 0-20 ppm range.

KH is carbonate hardness. This mean inorganic carbon which is required/used by the nitrifying bacteria, If you wish to raise KH some I would suggest putting a bag of crished coral in your filter. This gradually dissolves and will raise the KH. It mat take a bit of time for this to show up. I pil;d siggest you start with about 1/2 cup of the coral. If it is too mich or too little for your tank, you will see this from the KH and pH tests and you can adjust the quantity accordingly.
 

koigal

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Oct 13, 2019
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People are scaring you... a pH of 6,8 or 7 is just fine for koi. You don't have to change it.
Large pH changes aren't good for any fish. Just keep the water stable, and without ammonia (is that 0,25 I see there, it should be 0 (yellow) at all times, though it might be a false reading)
The danger with a low KH is that pH easily changes. You could get a pH crash but with a lightly stocked tank, regular water changes and monitoring of the water quality a low KH isn't a problem. Your fry is fine for now, it depends on how many there are, the temperature and until which size they have to stay there before it gets more complicated....
Thank you! There are 16 in the 40gal. and there for the winter. I have a heater set at 74F. Ammonia was yellow, it's the photo. I do a water change once a week. Should that be 10,15 or 20% each week?
 

koigal

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Oct 13, 2019
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Your test results look OK to me. But colors are somewhat subjective. Here is what I see.

pH is in the 7 to 7.2 tange.
Ammonia is 0.
Nitrite is 0.
Nitrate is in the 5 ppm range. This test is the least accurate of them and is especially so in the 0-20 ppm range.

KH is carbonate hardness. This mean inorganic carbon which is required/used by the nitrifying bacteria, If you wish to raise KH some I would suggest putting a bag of crished coral in your filter. This gradually dissolves and will raise the KH. It mat take a bit of time for this to show up. I pil;d siggest you start with about 1/2 cup of the coral. If it is too mich or too little for your tank, you will see this from the KH and pH tests and you can adjust the quantity accordingly.
I don't have a HOB, only 2 sponge filters and some ceramic media hanging in 2 bags over bubbles. What about a bottle filter with coral? Would I get enough movement with that to work?
 

the loach

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Aug 6, 2018
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I would go for 25% weekly... I'm not sure why you want to heat the tank, that will cause them to grow too fast and possibly outgrow the tank over the winter. Room temperature is already a summer temperature for temperate fish. Yes you can put the coral in a bottle filter..
 
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