nah, Randy's word is good for me.

I'll be interested to hear what he says. :smile:

Cheers.

Well I have to disagree on this part I have a 20g thats 9 months and a 29g thats 4 months old I have been faithful with 10% water changes...anyhoo last Thursday I finally bought a calcium test kit ...I know I know everyone should have one, I tested at 460 ppm in the 20 and 440 ppm in the 29. From what the instruction says that between 400-500 is ideal. I have maybe used 3 teaspoons of Kent liquid calcium in this time, I was to scared to use it cause I didn't have a test kit :redface: I think it is maintainence and water changes or maybe my tanks do not require as much calcium and I maintain with water changes or maybe I'm a fluke....anyways where was a going with this?.... :confused: .......I forget I'll be back

Agreed on the Ca thing. Frequent regualr water changes can keep levles fine assuming the Ca consumption of the tank is less than or equal to the replacement value. If you have a couple of softies or zoos only, etc, the Ca cosnumption would be minimal. Water changes would replace that. Add some larger LPS or SPS, you start moving towrds requiring supplementation.

Murray, I don't want to say you are wrong because obviously you aren't. What Bev wrote is acurate for the most part though. Yes there will be systems that just do fine on water changes but for the most part the Ca, Mg etc etc in salts will be used up in a very short period of time. Types of corals you keep, additives, light, temp all will play a role in how quickly Ca is used up and of course frequency of water changes will play a role as well. God knows I'm no expert, I've scratched my head so many times over reef chemistry I'm surprised I don't have a bald spot.

Doug

In a reality type situation water changes cannot possably maintain original Ca levels or any other level for that matter, unless you are doing 100% water changes.

think about it if you deplete 100 gal of water from 430ppm Ca to 380ppm Ca and you do a 20 gal water change with 430ppm CA is it going to raise the Ca level to ~390ppm, a 50% waterchange would only raise it to 405ppm. so if your tank consumes 50ppm in 2 weeks and you do a 20% change ever two weeks (which is a lot more than most do) after the first two weeks you will be at 390ppm, afdter 1 month you would be at 358ppm, 6 weeks 332ppm and 2 months 312ppm. please don't bother with the math this is aproximate as I didn't want to work it out this lait befor I head to bed, but it does show you what will happen on a tank with a high Ca demand.

as you can see you will need Ca addition other than from water changes.

Alk will be afected in a simular mannor also.

now for a lightly stocked tank this could go slower but you are never never never and incase you didn't get that I will say it again NEVER :mrgreen: going to maintain your levels with just water changes unless they are 100% changes.

Steve

Depends on what you keep. My Ca was always over 400 with water changes, four years into the hobby, until I put those damn sticks and those awesome clams in... :lol: :razz:

Oh, I should mention I use Kent salt for the higher Ca.

the only thing that will be different is the rate at which your tank drops as you have observed your old tank had a very low requirement so the drop was very slow, once you raised your Ca requirement with fuzzy sticks and a clam it sped up and became more apparent.

just out of curiosity what is the Ca level on fresh Kent mix?

Steve

I conducted a simple test and obtained a strange result.
I tested straight Victoria tapwater for phosphates. Result: undetectable.
Then I mixed 1 tsp. of baking soda in 1 c. Victoria tapwater and tested that for phosphates. Results: Turbidity of the test sample matched that of approx. 1.00 mg/l, against the color chart.
Here's the strange part...the colour of the test result was yellow, not blue!
Test kit used was a basic Hagen kit.
I'm not sure why the result would be yellow and not blue, but the test obviously measured something. :confused:
Anyone have any thoughts on this?

Mark, high alk will skew the test kit.