turbidity sensor

I dose kalk slurry (calcium hydroxide or pickling lime) to my fish tank to maintain alkalinity and calcium. I cobbled together a simple sketch that runs a mixing pump every hour and a minute or so later a peristaltic pump doses the tank.

It works great except for one problem. After the reactor is loaded with fresh kalk, the dosage starts slowly declining-noticeably so after a couple weeks.

I was wondering how involved it would be to use a turbidity sensor to dose the tank at a given level of turbidity rather than a certain time after the mixing pump has run. Is it feasible to combine this with Arduino?


Yes it should be feasible. Start off by taking some measurement to see what range of readings you get.

I didn’t get the turbidity sensor yet because I wasn’t sure it was very doable. I’ll order it and start goofing around with it.

@OP Did the solution work for you?

I decided not to go that route because I learned undissolved pickling lime caries a lot of undesirable impurities. A dissolved solution of pickling lime (calcium hydroxide) causes most impurities to precipitate from solution, due to high pH, I believe. Since the dissolved solution is clear, A turbidity sensor would not help.

The Ca ions are more likely the problem, combining with a.o. sulphate and carbonate to form insoluble salts.