Calcium depletion

[SpEd]

What is the expected calcium level depletion rate I should expect, if any, for a 75 gallon tank in 1 week?

Corals include:

1 toadstool
1 bubble
1 hammer
1 small colony of zoos

Thanks

 

[gooyferret]

It all depends on your tank setup and LR also....No way to tell without testing. HTH

 

[SpEd]

I have about 80 lbs of live rock, 4 tubes VHO lighting (2 acintic). Filtration is accomplished by 2 ehiem cannister filters.

ammonia, Nitrite, Nitrate = 0
alkalinity approximately 300 (using dip test, drop test has not arrived yet).
phosphate = 0
silicate less than .5

(Temporarily using Phosban in one of my canisters until I get my RO/DI system)

I decided to start testing once a week to start and then increase or decrease testing until I have established a baseline. My calcium was 440 last Sunday and read 440 again today. I was just curious what depletion, if any, i could expect.