Need Help with Low KH Level and High GH Level

[JGer]

Hello,

I have a 3-year old, 15 gallon nano tank. It contains 1 betta, 6 otocinclus cat fish, and 2 amano shrimp. My parameters are: ph 6.8 - 7.0, ammonia 0, nitrites 0, nitrates 5ppm, gh 179 ppm, and kh 35.8 ppm. Water temp is 78 degrees. I do biweekly water changes and dose with Aquarium Co-op Easy Green, Iron, and root tabs. My tank is heavily planted with low maintenance plants (anubias, java fern, swords, crypts) and I do not use CO2 injection.

Here is my question: How do I raise the KH to a more acceptable level without increasing the water hardness/GH? I have SeaChem Equilibrium, but do not know how to dose my tank enough to raise the KH without raising the GH. I do not want to use RO water.

Any recommendations would be appreciated.

Edited January 29, 2021 by JGer
typos

[Koi]

If I could ask is there a target kh level you are trying to achieve or are you seeing a negative impact that you think is a result of your kh?

[CT_]

equilibrium only raises gH.  seachem has a different product called "alkaline buffer" for kH

[Tory]

Just here to follow the thread. I have the exact same problem, realized it's my tap water that's causing it cause my tap water has really high gH and really low kH (higher and lower respectively than your numbers) and I end up with pH swings sometimes. I've tried googling this before and it seems that lots of people have this problem but I've yet to find someone with a solution lol

[Emika_B]

Tory - I’m following this one, too.  GH is at least 300 ppm, KH is 0-35-ish depending on the test.  Fortunately my pH has held steady but I’m trying to boost the KH to prevent swings.  Good luck, all!

[Will Billy]

CT_ is correct, seachem equilibrium boosts your GH, and seachem alkaline buffer boosts your KH. A few things i will caution you about tho. Alkaline buffer will boost your KH, but it will also boost your PH too. Those 2 are interdependent. Your KH of 35.8 is low, but as Koi points out, are you having health problems with your fish? Are you having problems introducing new fish? If you arent having any issues, i wouldnt fix whats not broken. Especially if you have otocinclus catfish. Otos are not the best adapters to wild changing water parameters like some other fish. Wild swings in PH or temperature isnt good for any fish technically, but especially otos. Have you tested your tap water? If your tap water is the origin of your problem, and you adjust your PH and KH, you will have to continually adjust it with every water change. Thats gonna be a bit extra hassle, and more bottles of alkaline buffer ( more money spent ), with every water change. If you are having issues, i am un-aware of any natural way to boost just your KH without also boosting GH too. Off the top of my head alkaline buffer is the only solution i can come up with. 

[Koi]

@Will Billy summed up mostly what I was getting at. Especially the money part haha.

Now I'm not experienced in raising kh but I'd like to mention just out of safety if you do raise your kh, you should probably raise it incrementally over a few weeks, months might be better. So lets just say for example 35ppm( roughly 4 dKH) I would try to slowly raise that by 1 degree (5dKH or about 90ppm) with water changes in the timespan of a month. And I could be wrong and it might not matter just adding it all at once but usually when I enter newish territory, I do it in baby steps.

A failsafe I would use is mixing the water separately in a bucket before adding it in so that you can test the kh just to make sure you're not overdosing.

Another thing is you might need to calculate how much kh you need to add according to how much water you take out due to dilution. It might be easy, I'm just a dummy to that kind of stuff.

This last part is more so a research topic I wanna offer since a few people mentioned they were looking for options. I will preface I have never done so take this last part with a grain of salt, but baking soda was an option Ive seen thrown around along time ago. And again I'm not saying it is a solution, I just know people have done this so please research thoroughly,

Edited January 30, 2021 by Koi

[Mmiller2001]

Easy, to lower GH, mix your tap with RO or distilled water. You will just have to try varying amounts and record the change to GH. It's roughly half - xppm GH in 1 gallon, add 1 gallon RO/Distilled 1/2xppm result, there about. It's easier to think in degrees hardness, to convert ppmGH/KH we would divide by 17.9. So your GH of 179/17.9=10dGH. With your live stock and plants, I'd shoot for 3dGH. To raise KH, I like to use K2CO3 (Potassium Carbonate). You can pick this up on amazon for like 16 bucks. It will last for a long time. It dissolves well too. I use https://rotalabutterfly.com/nutrient-calculator.php to calculate the amount to mix. But 2.5 grams will raise you 1dKH per 100 liters (26.4~gallons). For your tank, 3dKH should be fine. 3x17.9=53.7ppm KH. Hope this helps.