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?

http://www.ebay.com/itm/Turbidity-Sensor-Liquid-Particles-Suspended-Turbidity-Value-Detection-Module-Kit/252085533564?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D2220072%26algo%3DSIC.MBE%26ao%3D2%26asc%3D41376%26meid%3D020b025ab90e4e4ab6761e408b528243%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D361617131383j

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.
Thanks.

@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.