thx Greg, I see you have look for me even on forums thx for your help

going back to that checker. I have prepare the kh4 solution. I have test it and my kh test did not showed me a kh4 (actualy, colour never changed). so I did a kh test on some distiled water. same problem. so I have trash that bad test kit.
Same thing for my ph test. before to use it in the ph drop check, I have test it with a know solution ph 7.01. the test showed me a ph of 6. I have trashed that bad test kit to.
We allways read to make sure our test kit are good. I have read this recommandation for month without doing it. I have paid for beacause I have test my water with those bad test for a while. So folks, help yourself and follow those good advise about test kit. If your lover is an aquarist to, what a gread valentine present it would be to check his/here test kit

so now I assume my solution is good beacause I followed the recipe well. I have a beter ph reagent (the one that came with the ph drop checker).

I have install it in the tank 30 min ago. colour is dark blue for now and I"me waiting.... and waiting again.