You need the lightweight Moler clay based cat litter.I understand that cat litter has a high CEC so its good for planted tanks but if its the clumping type does it make any difference?
Hi The only down side to using cat litter as a substrate. Its so light any water fish shrimp movement and it moves about.
It was just because we have really hard tap water and washing it in the way that @foxfish mentions just filled up all the cation exchange sites with Ca++ ions. I use rainwater in the tanks, so I keep "soft water" fish. @foxfish will have soft water out of the tap, because Guernsey <"is a "granite" island">.While @dw1305 mentions in another post, leaving out in the rain for six months !
Thanks both.The best way to clean hard cat litter is in a large bucket of water with an outside hose pipe.
The bigger the bucket the better, half fill it with the litter and run the hose to overflow the water.
keep going until it runs clean and it is then safe to use.