Raising Carbonate Hardness

[Trebs]

I'm really getting sick of my ph crashing due to low kh. I do do a lot of w/c but my fish load and the low kh out of the tap means this keeps happening.

What are the best methods for raising kh? (preferably natural).

My KH out of the tap is about 2-3 degrees (not sure what this is in ppm - will check and update my post) and lower in the tank. At what level should I aim to keep my KH to keep PH stable? Ideally I'd like to keep my PH stable somewhere between 6.5-7.

Thanks.

[lesley]

Hello Trebs,

Calcium Chloride, Calcium Sulphate (Gypsum) and Bicarb soda will help your carbonate hardness. You will find that the first two do not affect the pH much but do not raise the carbonate hardness as much as bicarb soda.
Bicarb soda does raise the pH so if you are going to use that, you will need to experiment. You will also find that carbonate raised by bicarb soda gets used up quickly. I run my tanks on on a kH of about 2-3, but you do need to keep an eye on that pH!

The first two are best used in liquid form Ca.chloride (Stopit or Pitstop, agricultural chemicals for calcium deficiencies) and Ca.sulphate (Gypflo, another calcium supplement).

Calcium carbonate will raise your carbonate hardness a little, but also raises the general hardness.

HTH, Lesley

[Trebs]

Thanks for the reply. I'll have to have a go at that.

I was kinda hoping there would be a way for me to adjust the KH to about 5-6 without instantly changing the PH (obviously the increased buffering capacity will effect the PH over a short period of time).

[Dave76]

You can try adding some limestone or crushed coral to increase the KH - it will effect your PH, by how much depends on how much you add.

It might pay to experiment on a spare tank or tub of water first and go from there.

In my cichlid tanks the PH raises by .1 or .2 for each 3-5 of KH.

Hope this helps

Dave

[Trebs]

I have a bag of crushed coral (pieces are 2-3cm in diameter). I'll try it on one of my tanks and hopefully get an idea for how much to use once I get the new system in place. I'll try that and post my results.

[Trebs]

I've done some additional reading namely in planted tank and african cichlids sites. They are suggesting the same sorts of things which is good to hear. I now have a much clearer idea of how to proceed.

Thanks everybody.

I'll post my results as I go along.

[Trebs]

I added about 3 teaspoons of baking soda to my 90gal. The KH was raised from 1 degree to 3 degrees. The ph came up quickly from <6 to 7.2. I removed so fish to reduce the bioload. I now have 2 pairs in the tank which are currently breeding. It's been 4 days and the kh and ph are both constant at 3 and 7.2 respectively.

[Aurora]

You can buy kH powder that will set the pH to a certain value. I brought kH powder 7.0 which increases the kH and brings the pH to 7.0. I have also seen 6.5

This is good because you dont have to worry about adding too much and sending the pH too high. It also means the pH will always be constantly 7.0, whereas if you are adding something else that happened to get it to 7.2, it might not be the same the next time you add it.

[Trebs]

I don't want to touch buffers. All you really need is a good water ager and a good understanding of water chemistry.

[lesley]

Hi Trebs,

I found the when I was learning what went best that the couple of buffers I tried were disastrous. I now have a basic mix of the previously mentioned ingredients that I add in small amounts and watch the fish for any necessary minute adjustments. You will be finding that you can't add much carbonate hardness without raising the pH!! Which is not really surprising, if after all, carbonate hardness is alkalinity, from my basic understanding.

I manage to run mine now at just under 7 and still maintain enough carbonates for the fish and plants to be happy and the water stable. I am also using crushed bentonite which I believe might be helping to stabilise as well - the jury is still out on that one.

Lesley

[Trebs]

I'm not to worried about where the PH has come up to. The main thing is that it stays there. 5 days in and I'm getting a PH reading that has varied at most .2 . I'm really happy with this result. Now I can change different amounts of water without effecting the ph too much - which is a luxury I've never had.

I can't wait to grow out my next lot of fry in stable conditions with some added hardness. I expect there to be a marked difference in growth rate, better shapes and less defects.

Thanks again for the help this will make a big difference for me.

Next I'll look at the gh and maybe look to raise that as well for the fry.

[lesley]

I don't know what you are currently using, but calcium carbonate (available at LFS) will add to general hardness as well as carbonate hardness. Baking soda only adds carbonate hardness.

Lesley

[Trebs]

Yeah long term I want to add both. I think it will be important once I start trying to grow out fry in the future.

KH directly effects PH, but what relationship does GH have with PH and KH? I'm still a little hazy on how that all works.

[lesley]

Hi Trebs,

this is a good place to look at
http://www.thekrib.com/Plants/CO2/

Calcium carbonate will add kH and general hardness in equal amounts as I read it. I find it more stable than bicarb soda. I had some excellent calcium carbonate from an LFS, then bought some at a chemist and couldn't get it to dissolve properly so I've just been using bicarb. Must get some more dissolvable calc.carb. though

HTH, Lesley

[milt master p]

Hi trebs,
In the past a tank of mine suffered two pH crashes (lost several fish), presumably due to the combination of low carbonate water (to keep discus happy and breeding) and what I presume was the plants (I had thin val at the time) assimilating CO2 from soluble carbonate ions in the water and reducing what was already low carbonate levels. My fix was to get some crushed coral and sprinkle it on the gravel. It has worked a treat. In theory, the lower the pH gets the more the coral will dissolve so it kind of self regulates the carbonate level. I use about half a handful for every 100lts.
I thoroughly recommend crushed coral and think it a far better alternative than mucking around with carbonate salts which can cause rapid pH changes.

Cheers,
Paul

[defa]

I have just started my 3rd discus set up and have never had any problems with the discus so I thought to try my hand with the planted tank. Plants are not doing too well. The KH dropped so low after 6-8 weeks that you could not get a reading from the test kit, so I started to use KH up tablets, 1 tablet up's the KH by 20ppm in a 300lt tank. As the KH came up to 60ppm, The fish improved heaps, swimming around, begging for food 24/7, heaps better colour, the PH also can up from 7.2 to 7.4 and has not changed much since. I brought the KH up to 80-90ppm so I could turn on the CO2 kit, this took about 2 weeks to stabilize in the mid CO2 range, but I still need to add 1 tablet every week, 2 if I do a water change. My PH seems to stay about 7.2-7.3. The plants still have not kicked on much, all iron levels etc and lighting is good (2 growlux compacts & 2 white compacts for 10hrs per day in a 4ft tank) The algae has matched the fishes responce to the improvements, I need to clean a slimmy dark green algae from the gravel & plants every second day.
If anyone has any hints to help slow the algae up until the plants can catch up, please let me know.