I am adding a sump to my operating tank.

[sampsonndelila]

This might be tough but I want to add a 75 gallon sump to my current 35 gal sump.
I want to put 10 inches of sand or sub straight to one side and rubble and green to the other side.
I think if I put clean sand in there it will not spike my ammonia or nitrates.
Any thoughts?

I have 300 gal. tank running for a year in the current configuration. I have 500 lbs of Live Rock, 30 or so fish, with minimal coral.

[Ping]

Why add the rubble? It can be a detritus trap in vegatative fuge.

What length and width will the vegatative fuge side and the DSB side be?

[BA]

i agree with ping on the rubble***

what do you currently have in the 30 gallon sump? Also why add the 75 gallon sump if things are doing well, or are you having problems with nitrates and stuff like that? 500lbs of live rock is already a killer filter

[sampsonndelila]

The main reason I was thinking of adding the 75 gallons was more stability and temp control. The MH lights heat up the water something bad; I figured the more water the better.

Rubble was just an idea, I am not having nitrates, I never did. I had med high ammonia when I switched to the new tank it was gone in a week. I merged two established tanks.

My thought now was just to add the 75 gal with nothing but water. I might add some algae as well. I don't know just a thought. I might add the deep sand bed later, slowly.

The 30 gal sump is working fine but I just have some live rock and a protein skimmer in there. Skimmer is an Octopus.

[sampsonndelila]

oh, and the sump is split 50-50 4ft box.

[Squiers007]

If your 30 is getting the job done, then I would just add the 75 as water only to increase your total water volume. This will help out with your temperature problems especially if you put a couple fans blowing on that tank to increase evaporation. If you are still having temp issues you may have to consider a chiller though. Good luck.