recirculation calculations

[philworrall]

Given any sized tank and sump.What is the ratio of recirculated water through the sump to that provided in the tank by for example power heads.
I am trying to calc volumes and come up with the appropriate main pump and power head for my tank.
I plant to have a mixed tank with SPS and a few fish 5-6 perhaps, although I will probably get started with soft corals.

Thanks for any advice.

 

[Mouse]

Watcha talkin about Willis?

Im presuming that you want to know the correct circulation rates for any given gallonage. Firstly, i think you need to decide how to manage your circulation. Personally i would stay well clear of powerheads because:

1) their ugly
2) they suck up beasties like cukes, nudi's and anemonies.
3) They require alot of maintenace, cleaning screens impellars etc.
4) They dont tend to last a huge ammount of time, especially when connected to a wave maker. To lengthen the life of PH's and pumps used with a wave maker you should ensure that the controller has a soft start facility.

So basically i would go with a closed loop circulation system controlled by a soft start wave maker, and if possible some sort of occillators on the end of those, like sea swirls or something.

To calculate the circulation you should multiply the total aquarium volume by something between 10 - 15, which should give you the GPH (gallons per hour rating).

So a 200 G tank would require the following calculations.

200 x 15 = 3000

So i would need 3000 GPH circulation for this system. I feel this would be adequate for all corals including SPS. 10 x the total volume would give you a figure more suited to LPS and soft corals. Allthough with correct placement SPS's could be grown.

This calculation should remain seperate from your demands for other pieces of equipment running in the sump. This total equipment requirement can then be used to decide how big the pump needs to be for the sump. Dont include the sump return as part of your curculation system because its just a bit lame IMO, especially when your talking about a factor as important as this. Better to go for a bit more than less, it will mean that your system will look better and require less manual disturbance. Im not sure what the actual figures for a reef crest are in terms of circulation, but if i told you it would make the above figures look like a minute girly bottom burp in comparison.

Also make sure that your velocity isn't too high or you will be looking at a tank of skinless inhabitants by the time you get home. Make the outlets large, and the velocity wont be so big. There are suggested diameter/flow recomendations that would ensure that you dont have a velocity thats too aggressive. But its very dependant on the size of aquarium and the inhabitants you wish to keep.