AE Design 4 dKH Solution - 250ml

Why do you need this? Aquarists wanting to know the correct CO2 level in their tanks often use a CO2 glass indicator bulb that changes colour to show the right level of CO2 in the water. The CO2 bulb manufacturers often tell us to use aquarium water with a few drops of Bromothymol Blue (pH indicator liquid). But this doesn't work accurately if you have any kind of wood in the tank. So you need to use pure water with exactly 4d of Carbonated Hardness (KH) in your indicator. AE supplies this. No fuss, no worry. You can't go wrong with this pre-made and accurate 4DKH solution and a drop or two of Bromothymol Blue in your CO2 bulb. Keep it sealed and out of the light and it'll last for years!

Would highly recommend this to everyone. No more guessing game on CO2 in the tank. Just add a few ml in your drop checker and a couple of drops of BLUE ph test kit reagent. Pop into tank accurate results in hour or two. Brilliant product. The economy side 250ml give around 80 test (3 ml each time in drop checker) that works out around 10 pence per test.