Sizing a return pump

[PghReef]

Need help choosing a return pump. Pretty sure I want to go with the reef octopus varios pump.
Tank is 90gallon RR with a bashsea 30x18 sump. Sump will be under the stand with a head height of about 4-4.5 feet and return over the top of the back of the tank.

Should I get the varios 4 or the varios 6?

 

[mfinn]

On your 90 you really only need 450-500 gph, so the VarioS-4 would work fine but you would be running it close to maximum.
If you got the VarioS-6 you would only need to run it around 50% or so.
Without knowing exact plumbing size, and fittings this is just a general guess.
I would probably pick the VarioS-6.

 

[PghReef]

I was always under the impression that larger is better and you can throttle it down but am afraid that if it somehow defaults to high it can cause damage it overflow the display if unnoticed after a power outage or something.
Plumbing will be twin 1 inch drains Herbie setup and 1 inch return. Am thinking itll be pretty much a straight shot with some 90s to go over the back rim of the tank.

Was even thinking of doing a dual varios 4 setup for redundancy but they're pricey.

 

[Kfactor]

Just buy bigger then what you need me turn it down

 

[mfinn]

I was always under the impression that larger is better and you can throttle it down but am afraid that if it somehow defaults to high it can cause damage it overflow the display if unnoticed after a power outage or something.
Plumbing will be twin 1 inch drains Herbie setup and 1 inch return. Am thinking itll be pretty much a straight shot with some 90s to go over the back rim of the tank.

Was even thinking of doing a dual varios 4 setup for redundancy but they're pricey.

If you were under a tight budget the VarioS-4 would work just fine. Really anywhere between 3x the tank volume and 5x the tank volume is generally considered normal.
The VarioS-6 would give you some wiggle room in plumbing design.
I've never heard of a controller/pump combo defaulting to max power.

 

[dank reefer]

Id go with with the 6 in case you wan to add some manifolds in the future you don't have to buy another pump. As said previously, you can always throttle it back to 40-50 % and still have room to give it more power.

 

[PghReef]

Varios 6 it is then. Budget isnt that much more and if itll suit my needs better then cant go wrong, buy once not twice. How well do those icecap battery backups work on those pumps I see brs has them listed together on the site.

 

[dank reefer]

How well do those icecap battery backups work on those pumps I see brs has them listed together on the site.

Instead of getting a battery backup for your return pump, look more towards getting one for your wave makers in the DT. Its more important to make sure that you are providing good gas exchange than turning you water over through your sump in case of a power outage. Just my thoughts.

 

[PghReef]

I have one for my powerheads already but dont want to sump to sit stagnant and foul if I lose power. Then when it comes on dump ammonia into the DT.

 

[mfinn]

Varios 6 it is then. Budget isnt that much more and if itll suit my needs better then cant go wrong, buy once not twice. How well do those icecap battery backups work on those pumps I see brs has them listed together on the site.

Years ago I bought a couple of the ETM backup batteries.
As luck would have it, nearly 4 years went by before I had a power outage and the batteries were nearly useless.
They did lose their charge, or I did something wrong.
I don't trust them.

 

[MichaelReefer]

I've always been one of those people that thinks you should always go bigger because at least if you want to upgrade later you wont have to buy a new one, not to mention it will have less strain on it because you're not maxing it out 24/7 for years (if it lasts that long).