We have a MutiTest 1200-V test kit. We use bottle indicators and not strips. We also bought an Ammonia NH3/NH4 test kit. Upon testing we found 0.25 ppm of that contaminant in our 17000 gal pool.

Do you have some more suggestions. Do you think replacing the sand in case there is organic matter on the sand would help? It's either the sand or the water. To me I would try the sand first.

Thanks for all your help.