How to raise KH

[Julian D]

I have a guppy breeding tank and KH is vary low and I am have guppy with bent spines how could I raise KH I was thinking marine salt. 

[Fish Folk]

Crushed Coral will slowly raise the KH and GH in your aquarium. I think that somewhere here the Co-Op has recommended 1 lb. of crushed coral in substrate or in a suspended mesh bag per 10 gal. of aquarium water.

[Emika_B]

I will add this for what it’s worth - your substrate may be messing with your KH reading.  I use Fluval Stratum, a “buffering” substrate.  My KH is low, 3 or 4 degrees if I’m lucky.  And that’s with 4 lbs of aragonite added to a 40-ish gallon tank.  I just have to trust that the substrate will keep things from going crazy with the pH.  Fortunately, all of my other readings are good and my fish are happy and healthy.

Good luck!

[Hobbit]

If you need to raise your KH quickly, you can use baking soda. Start with 1/4 tsp per 5 gallons. Dissolve the baking soda in a jar of tank water before adding it in. After a few hours, retest and see where your KH is.

My tap water is extremely soft with no KH to speak of. I add baking soda with each water change, and I also keep crushed oyster shell in my tanks.

Baking soda will raise your pH as well as your KH, but that looks like a good thing in your case!

[Steph’s Fish and Plants]

Baking soda and crushed coral are both great, I’ve also used alkaline buffer by seachem since that’s what they sell at my LFS, I believe the dosing for both baking soda and all buffer are the same. I wouldn’t use marine salt though if you have live plants, and if you do be Very careful. Guppies can acclimate to salt or at least brackish but they need time, so you wouldn’t want to raise the salinity very much at all so you’ll have to add very very little salt, which might not end up adding enough Kh to get you where you need anyways.

I really like crushed coral the best because it is set it and forget it, and occasionally test it. For alk buffer and baking soda you need to test regularly and adjust dosing patterns to compensate. If you have a larger tank or multiple tanks, your lfs might have a 40lb bag (that’s what I went with).

[Guppysnail]

The easiest way I found that does “wonders” lol for my guppies is wondershell.  I also use api liquid calcium and epsom salt when I’m out of wondershell. I did at one time try dr. Turtle calcium block but I was unsure of dose and it upped my ph to high...I’m sure that was my dosing not the block but I agree your ph might be a bit low for guppies. Being what they are used to whatever route you choose go slow. Best of luck my favorite thing is guppy fry lips 🙂

[quikv6]

Wondershell would only really affect GH, and it looks like you alread have very high GH (which would probably be a good thing for guppies).

I use crushed coral as a substrate, and add baking soda as Hobbit recommended. Do it slowly and carefully, as not to hock the fish initially. After that, it should be easy to maintain, once you know how much baking soda to add to a given volume of water, to get to your desired KH/PH.

[DShelton]

On 6/9/2021 at 10:12 PM, Fish Folk said:

Crushed Coral will slowly raise the KH and GH in your aquarium. I think that somewhere here the Co-Op has recommended 1 lb. of crushed coral in substrate or in a suspended mesh bag per 10 gal. of aquarium water.

If your source water is acidic, or only slightly basic. It will also raise the pH. The amount depends on your starting point.