Cam07 Posted November 9, 2015 Report Share Posted November 9, 2015 I have a question about gh and kh. I have never had a test kit for that and got one yesterday so been playing with it. We are on trickle feed water here meaning our tank is fed by mains water to a point then rain will fill the rest of the tank that we use for house water. During normal times we are using mainly mains supplied water which has a ph of 7.8 and gh of 13. One tank that has been running for a few years has a bit of crushed coral substrate in it has a ph of 8 and gh of 19. I asuming the substrate is providing the extra to raise the gh which in turns provides stability of ph 8. Since we have had the rain tanks are full and I set a tank up on the weekend which now has a ph of 6.8 and both kh and gh don't even register. I need to get the ph up to a stable 7.8 and have been told I need hard water for the cichlids I am getting. To raise this instead of using buffers, which I am assuming if the hardness is not correct will fluctuate rapidly, can I use a substrate to raise the gh and kh which if my assumptions are correct will raise and hold ph stable. I could be completely wrong and would be very appreciative of any advice. Link to comment Share on other sites More sharing options...
P4rker Posted November 10, 2015 Report Share Posted November 10, 2015 (edited) I use Rainwater from the water tank with 0gh and 2 kh. When i do a water change i use a 25ltr bucket i add 12.5ml of epsom salt and 7.5ml of bicarb soda. That will get you close enough for malawi water. Gh = general hardness. Kh carbonate hardness (this one keeps ph stable). Your crushed coral definitely helps. Tried to keep it as simple as possible. Edited November 10, 2015 by P4rker Added info Link to comment Share on other sites More sharing options...
P4rker Posted November 10, 2015 Report Share Posted November 10, 2015 Was pretty brief, i feel i should add more. Your substrate will buffer the ph. Calcium carbonate (crushed coral increases gh and kh in equal parts). Gh is just general hardness. Cichlids like hard water. Of you use the quantities with rainwater or similar properties to what i mentiones you will get the ideal water properties you're after. Lake Malawi cichlids PH: 7.8 to 8.5 GH:10 to 20 or 180 to 350ppm KH: 8 to 12 or 140 to 220ppm Temp: 23 to 28c Link to comment Share on other sites More sharing options...
Cam07 Posted November 10, 2015 Author Report Share Posted November 10, 2015 I like simple, thanks for that. I have tried buffers (powders) in the past and had no luck just up and down all over the shop so was thinking that a substrate such as calcium carbonate gravel would help keep it stable, until at least we run out of rainwater and back onto the tank water. Again thanks for the reply Link to comment Share on other sites More sharing options...
P4rker Posted November 10, 2015 Report Share Posted November 10, 2015 If it drops and rises that means you have a low kh. High kh stabilises ph. Short answer is yes your substrate is helping. It won't keep it stable if you keep adding fresh water with low kh. A way to help is throw some calcium carbonate into a bag and put into your filter. The more water that passes over it the more it will provide for your tank. How big is your tank and what type of filter/s are you running. Handy tip when adjusting water is to be careful of salt. No influence on kh but it has a ph of 13. Its okay if you're wanting a higher ph and have a high kh. Always wanted to create a basic buffer for tanganyikan cichlids just never come across a good cheap DIY recipe Link to comment Share on other sites More sharing options...
P4rker Posted November 10, 2015 Report Share Posted November 10, 2015 [MENTION=231]gingerbeer[/MENTION], do you have a DIY recipe for replicating tanganyikan water? Particularly from RO or rainwater? Link to comment Share on other sites More sharing options...
