Two Questions...Overflow flushing and 250 MH on my 20 long

[c9miles]

Question 1
I just upgraded my return pump to a mag 9.5 and now my overflow is making the toilet flushing sound every few minutes. I enlarged the air hole at the top of the standpipe a little, but it didn't seem to help much. Does this mean my return pump is too powerful for my overflow, or is there another way to fix it?

Question 2
I'm thinking of upgrading my 175 watt MH to a 250 watt MH over my 20 long. I want to be able to have a clam or two and I'm worried that they might not get enough light with the 175. I have the light elevated about 15-20 inches off the water. Will this be overkill on lighting for my coral, or will I be ok with the upgrade? I'll also be using a fan over the sump for cooling.

Thanks,
Chad

[Doug1]

What were you using before the upgrade? if its a big increase you will prolly have to retweak it

[Geoff]

175w on a 20l will be plenty of light for a clam. a 20l is shallow. not much light loss due to water depth. i would stick with the 175. 250w on a 20l, you will quickly run into cooling problems.

if you are worried, lower the light a little. move it closer to 10" over the waters surface.

G~

[c9miles]

That sounds good. I wasn't sure if the clam would be starved for light, but I can lower the pendant and that will save me some money if I don't have to upgrade ballasts and everything.

Also, I was using a Mag 5 as my return, but I built a taller stand so I upgraded pumps to a Mag 9.5 to counter the head pressure. What kind of tweaking is necessary to keep it quiet?

Chad

[Geoff]

what size pipe is your drain? i am guessing it is a 1" pipe. you are at the maximum. you may just need to valve the pump back a bit.

does you overflow have a Durso standpipe on it? if so is the upward pipe a size larger than the bulkhead size?

G~

[c9miles]

Yes my bulkhead is 1" and there is a DIY durso standpipe. The pipe is the same diameter all the way down to the bulkhead.

If I were to put a valve on the pump, should it go on the intake or the output? Thanks again for the help.

Chad

[titanfan]

Personally I think a mag 9.5 is way to strong of a return pump for a 20 long. I am from the thought that sumps arnt made to add flow to a tank. Powerheads and closed loops should be for flow in a tank. Don't ever put a valve on the intake of a pump though. One on the output would be fine. A 175watt halide should be good for that tank. You could lower it if you wanted but air does not weaken light that much when you are talking a few inches. I would just have it at the level that gives you the spread of light you are looking for.

[c9miles]

I agree that the Mag 9.5 is strong, but it is pumping up to about 4 feet, and it is also split between two returns..one in each upper corner of the tank. After that, it is considerably weaker. I'll try putting a valve on the output and gearing it down a little. Maybe that will help control the flushing noise, and slow the flow through my sump.

[thekid55]

do you have a CPR siphon?

[c9miles]

Nope no siphon. I drilled the back with a dremel, and same for the returns in the upper corners.

[Geoff]

always put the valve on the outlet of a pump. not a good idea to starve a pump.

G~