Water turnover rate

[aravindk]

I am installing a new sump in the basement and pump the water to the first floor. I am using Gen-X PCX70HP external pump and it looks like it is pushing too much water to my tank, more than the overflow can handle. The water comes dangerously close to the top edge of the display tank.

a) How can I salvage the situation? Should I try to reduce the flow coming in
(by closing in the ball valve) or increase the flow that goes out or both? and how?

b) What is the ideal turnover in the display tank? How much is too much?

Any help is appreciated.

 

[JM]

I would use a ball valve to turn down the flow out of the pump. You really cant increase the flow out of the tank because the overflows can only accept so much water, it can't be increased.

 

[vsnsofadrgn]

i had the same problem. ball valve worked great.

 

[tecwzrd]

Most external pumps can handle a little back pressure so if you don't have to restrict the flow too much using your ball valve then that is the easiest solution.

The best option is to T off the return to go back into the sump (also using ball valves) and divert the excess flow not needed back into the sump to keep from putting any back pressure on your pump.

Turnover rates vary depending on type of tank i.e. FO/FOWLR/REEF but if not a reef tank I'd strive for a 15-20 times turnover. If it is a reef tank then flow will be more dictated by the types of corals you have.

 

[aravindk]

It is a fowlr now, but will be a reef hopefully soon. Mine is a 72 gallon and the pump based on the head loss calc in reef central, seems to be pushing at about 1000 gallons about an hour. I guess I am pretty close.

T-eeing the excess water back to the sump is a good idea, although I would hate to cut the pipe again. But thats what I said the last 15 times or so...

One another question that I have is that the pump seem to be putting tonnes of micro bubbles in the display tank. I noticed there were leaks in two places in the plumbing. I am going to seal them with teflon and run the pump again to test.

Can there be any other reason other than the leaks, that would cause microbubbles? I dont see any bubbles in the sump.

 

[tecwzrd]

Since you don't see any bubbles in the sump (I assume you have quite a few baffles) then it could be coming from a small hole sucking in air on your pump but with that many GPH going through your plumbing I think you would notice any holes in your plumbing pretty quickly by water shooting out 8O

 

[Ziggy953]

What kind of plumbing are you using that needs teflon tape?

 

[aravindk]

Since you don't see any bubbles in the sump (I assume you have quite a few baffles) then it could be coming from a small hole sucking in air on your pump but with that many GPH going through your plumbing I think you would notice any holes in your plumbing pretty quickly by water shooting out 8O

Yes. It is leaking in two places pretty big.

What kind of plumbing are you using that needs teflon tape?

I use PVC pipes. The inlet thread & outlet thread of the pump. The pump uses 1" outlet, I raise it to 1.5" right after the pump run through the ceiling and then right before the tank I reduce it from 1.5" to .75". I have two or three threaded components where I reduce the size near the tank. It leaks there too.

 

[Ziggy953]

That's what I thought just checking...I solved that problem on my tank with lots of teflon tape....LOTS PVC doesn't like to seal on it's self and it take a lot of teflon tape to get it to work....or you could go with the fittings that have gaskets in them. I would consider that with the amount of water flow you pump moves!!!

 

[tecwzrd]

Any loose seals or connections that are not 100% airtight can admit air which causes microbubbles and troubleshooting can be quite difficult with that many pipes/fittings.

Hopefully you will be able to plug all the leaks.

 

[aravindk]

The thing is I have leaks only where there is a threaded fitting. I tried to avoid the threads wherever possible;

Looks like both of you seem to imply that 1000 gph is a lot??? When you say shoot for 15-20 times of the volume, being my tanks is 72g, I thought 72g*15 about 1000 gallons, right? Is it not a reasonable flow?

This 1000 gph estimate is based on the reef central head loss calc, based on an equivalent pump. So in reality the flow would be more or less.

 

[melosu58]

Moved to general Hardware and equipment discussion.

 

[tecwzrd]

15-20 times turnover is recommended for good circulation/oxygen exchange but it doesn't have to be all done in the sump. It can also be done using a couple of power heads or a closed loop system.

Not that other people haven't had that kind of flow through there sumps but typically they have multiple overflows and 125+ gal tanks.

Tank size isn't as important as making all seals airtight.

 

[aravindk]

Thanks for the suggestion, I added another pipe to divert some water back to the sump. This reduced some water flow in the display tank.

Even after diverting some water, the flow is apparently too much, and I have a non-stop sand storm in my display tank. What are my options now?

Pl. help.
Arvind.

 

[tecwzrd]

Smaller pump or more water diverted to the sump. Are all your returns at the surface? How many do you have split for returns to the tank?

 

[aravindk]

The returns are split into two and they both are on the surface.

Also, If I increase the water flow that is returned to the sump, that creates a lot of bubbles in the sump.

 

[chase33]

Your pump is pumping more water into your tank than what is coming in through the overflow. You want to try and match the two rates (overflow and pump) as closely as possible. Find what your overflow is rated for and try to match it with a pump that will return that volume. If you don't want to get a new tank then what you need to do is divert the some of the water so that it doesn't go into the tank as quickly as it leaves. As mentioned above you can divert some water back into the sump. If this isn't enough then you need to divert more. You could add another line back into the sump but ultimately it sounds like your pump is too strong for you overflow. You might also try to include as many elbow and tees into your plumbing to decrease the rate. I'm not sure how much each decreases but there are calculators that can help.