[CatCityGary]

Recently set up a new 100gal tank. 60x18x24. It is a drilled tank with a sump below. Sump is very large with approx 4 gallons of bio balls. When I got ready to turn it on the first time it turns out the large pump (1500gph) was toast and wouldn't start up. I had a much smaller pump that I use for a small tank (approx 400gph) that I hooked up just to check and make sure all plumbing was working properly with no leaks. On my trip to the LFS the dealer suggested that since I had an ok flow through the sump I didn't need to purchase a larger pump. She suggested I buy a circulation pump to place in the tank for water movement. Her theory was as long as water was flowing through the sump it was working ok. With the addition of the circulation pump for water movement I would have enough flow for the tank. Parts of this theory sounds pretty good, but it was something I have never heard before. If water is flowing over the bio balls, does it really matter at how much speed or volume the flow is as long as there is constant movement? Also don't really understand what you gain by the circulation pump in the tank other than movement of water in the dead spaces of the tank.
Any thoughts on this would be appreciated, thanks.

 

[fox]

I would consider almost MAXing out or getting very near the limit of your drain(s). For example if you use (1) 1" drain get a pump with at the LEAST 600 gph @ the head height req'd.

What size drain(s) do you have. That will determine the volume you can to push back to the DT.

Bio filtration will work very good with say 3x's turnover. Mech filtration on the other hand could use 6 - 10x's turnover.

 

[dielikemoviestars]

With a sump set-up, you don't need the standard 10x turnover most people recommend for tanks. 3x is a little low, but around 5x you'll be okay. A circulating pump in the tank would be great - as you said, it'll stop dead spots.

 

[PauloSilva]

You could always get creative with your returns so that you can avoid dead spots. Imho, 1 of the key features of a sump is to minimize the equipment in the display tank. I'm with fox on this one, go with whatever size pump your drains can handle.

 

[CatCityGary]

Well maxing out the pump is what I have always done in the past. And I have a 1" drain on the tank so could easily move up to a much larger pump. I guess where I was coming from with this question is, "is there a reason to max out the pump?". It seems to me that the key component of making a sump work is a constant flow of water over the bio balls. What I noticed when I put the small pump on is that I had achieved that already with the small pump.
I know it may sound petty but I have noticed a huge spike in my electric bill as I keep adding tanks and more tanks. My electric bill runs about $80/mo more now that I have several tanks going. I realised a big part of that is having a pump that sucks over 100watts of power running 24/7. Add to that heaters and lights and it all starts to add up. Then keep adding more tanks and all of a sudden it becomes a noticeable increase. As tight as it may seem with the smaller pump I use 25 watts/hr vs 110 watts/hr. I was just trying to understand what the additional water flow actually achieved for me. I was just trying to figure out "Why" I always max the pumps out, have to say I really don't see a reason for it and was just trying to figure out if I was missing something.

 

[fish_addiction]

I have a 110G tank with a 40G sump. I'm using a pump that's rated at 750 GPH, so really closer to 450-500 GPH at 4' below the tank. I did notice a spike in my electric bill along with the lighting, powerheads and cannister filter. With my cannister and sump, I'm turning over the total volume of the tank about 5-6 time per hour. I have added power heads and an jet system at the bottom of the tank to create upward flow and keep the **** moving towards the intakes. I think that you can get away with the pump you have as long as your tank isn't too overstocked (I have 40 small to medium size Mbuna). As long as Ammonia and Nitrites are reading 0, you are good. I would add a small Hydor Koriala powerhead to eliminate dead spots. The new ones are extremely efficient.

 

[fox]

A mag7 uses 60W and a mag9.5 uses 93W.

What most here will claim is 3x's turnover for bio. If the clarity of your water collumn is not too important go with the mag7 or similar pump that'll give you ~400 gph at 4' - 5' head.

If clarity is somewhat important ... most here will cite upwards of 10x's turnover for mech filtration. Then consider a bit larger pump and tee back to the sump anything your drain cannot handle.

 

[fish_addiction]

A mag7 uses 60W and a mag9.5 uses 93W.

What most here will claim is 3x's turnover for bio. If the clarity of your water collumn is not too important go with the mag7 or similar pump that'll give you ~400 gph at 4' - 5' head.

If clarity is somewhat important ... most here will cite upwards of 10x's turnover for mech filtration. Then consider a bit larger pump and tee back to the sump anything your drain cannot handle.

Agreed :thumb: