My tank is 5 monthes ole and i have been using since 1 monthe, the bottle says make sure you dont over use, i use half a capfull every 2 days on my 34 gallon. i actually just no more than 5 minute ago put some in my tank. if you are going to use this product i recommend putting into a very high flow portion of your tank. I put mine in inbetwwen my filter and powerheads so it gets dispersed appropriatly. Your rock will start turning color in under two weeks this is an incredible product for coraline algae. does not induce growth of any other algaes,

Every couple of days is fine, just make sure you monitor your calcium levels, you can even do daily doses once you get your levels stabilized. Like dosing with anything it is a balancing act.

i never bought a test kit yet is there another way that i can monitor levels?

I dont think so, You really need to get a test kit, A calcium test kit is probably around 15-30 dollars and so far all I have used work ok so long as you follow instructions. :biggrin:

Your best bet is to get a good calcium test kit (I really love the salifert Ca test kits).
Take a measurement, add one cap of purple up, wait about half an hour to make sure it's been spread around, then take another measurement. That will give you an idea how much one cap will raise your calcium. You don't want to raise it any more than 25ppm per day.
It's also a good idea to take a measurement about 24 hours after you dosed with it, just so you can get an idea how much calcium your system uses in a day.

you can get digital moniters they are expensive.there is an American Marine pinpoint calcium monitor http://www.jlaquatics.com/phpstore/s...uct_ID=pp-mcal