Water Changes

[gregzz4]

Do you know what your total system volume is ?
10% per week is a good starting point to see how things go

Lets say for argument's sake that your 250g holds 200g after rocks sand overflows etc, and your 70g sump holds 50g after baffles etc
So, for my arguement, we'll say your total system volume is 250g
You could do 25g WCs per week and all is good ...

If you can, try to figure out what your total system holds
It's good to know this, especially if you need to dose stuff

[Blind River Joe]

Good point I did not put my total system volume in the original post. The TSV including sump is 205 gallons. I have around 190LBS of live rock, deep sand bed etc. I can't say that there is any thing wrong with my tank and I don't want to be cheap but if I could cut the water changes down from 40 gallons to say 20 it would be nice. Thanks for the reply.

[gregzz4]

So you can cut your changes down to 20g/week and save lots of water/salt
Keep an eye on your ALK/CA readings as it will change with the lack of new salt water

[Spyd]

With such a large tank, you could easily drop down to bi-weekly water changes. I do 40G water changes bi-weekly on my heavily stocked 180g SPS tank. 40G bi-weekly, for your setup, should definitely be enough.

[Aquattro]

Originally Posted by Spyd

With such a large tank, you could easily drop down to bi-weekly water changes. I do 40G water changes bi-weekly on my heavily stocked 180g SPS tank. 40G bi-weekly, for your setup, should definitely be enough.

Agreed. You'd be better doing 40g every other week instead of 20/wk. I do 50g /biweekly and I'm satisfied with that.
BTW, you can't change too much water You can spend too much money doing it, but bigger water changes are never bad.

[Dearth]

In my 95 gallon I do a 14 gallon water change bi-weekly with no issues with corals or livestock.