my braces are underwater!

[glassboxkeeper]

when i turn on my return pump, everything is fine. then ranging from a few minutes to a few hours, the braces make contact with the water surface and look like this...


it stays that way until i unplug my pump. water never goes over the edge and wets the top. it's more of an eyesore than anything. tank is acrylic 225g, 50g sump, g4 skimmer, mag 12 return pump, with 1 maxijet 1200 and 1 rio 800 for circulation. what can i do??? is this a normal by-product of an acrylic tank bowing?

[brandon0350]

im thinking your overflow cant keep up with the 1200gph return pump? how big is your drain hole?

[glassboxkeeper]

drains are pretty big actually... 2" i think. they're probably too big, because they're really noisy. i wanted to go with 1.5" drains, but i couldn't find the right adaptors. water level in both overflows is lower than tank level.

[brandon0350]

is it a single overflow or dual? maybe the overflow slates are two small?

[EyeReef]

i had the same problem too, so I just lowered both durso standpipes by an inch or 2 and it worked. Not sure if it will work on your setup though. Good luck with it

[socalcreations]

The teeth on your overflow can not handle the amount of flow that you wish to put thru them. You have to either enlarge the teeth (knock out one or two), or throttle down your return pump a bit (ball or gate valve). HTH.

[glassboxkeeper]

i actually wanted to go to a stronger pump. my logic for wanting to go bigger than a mag 12 for a return is this...

- i read water volume in main tank should turn over 5-6 times per hour
- mag 12 pumps about 950gph at 6ft.
- i have 2 - 45's, a tee, and 2 90 degree elbows in my 1" return line, so that's less than 950gph

my tank is 225g with about 25-30 gallons in the sump. i didn't think the mag 12 was strong enough to change the water volume in my display the recommended 5-6 times.

so i guess i'd like to tweak the teeth in my overflows so they can handle more flow. how would i go about it? i'm thinking i should drain the tank a little and use a dremel. should i make the gaps wider or deeper or both? anyone ever do this before? anyone have tips? do i have other options?

[crstjohn]

I'd remove the teeth entirely and just have a single weir. Your water level in the overflow looks good for the Durso. Don't know why it is making noise. Does the level in the OF box vary (go up and down) and the Durso makes a sucking sound everytime? If so, you need to adjust the air vent to the standpipes. If this is happening, adjusting the air flow may solve your water level problem also. The Durso's should be silent. If yours are making noise, something is not working correctly. You have a few options to enlarge or remove the teeth on the OF. A dremel is probably the safest but will take awhile. A good jigsaw with the proper blade would quickly. A router would also work but make sure you have a good hold an it and take little bits at a time. (All of these will make quite a mess in your tank and house) Another option is to drill some holes in the between the teeth to enlarge the opening area. I would drill at the base of the teeth on every other one.

[glassboxkeeper]

Don't know why it is making noise. Does the level in the OF box vary (go up and down) and the Durso makes a sucking sound everytime?

water level in one overflow stays constant. the level in the other overflow varies 1-2 inches, but never drops below pipe to make the sucking noise. the sound comes from where the pipes drain into my filter sock. the sound is the water rushing through the hollow pipes with lots of loud splashing.

so should i chance drilling the overflow gaps or should i get a smaller return pump and forget about the notion of turning water volume over 5-6 times an hour? what are my other options??? if i leave it alone, will it lead to other problems down the road?

[phishphood]

flat weir....will possibly increase the chance, but it really depends on how well you tune it (ie how far underwater it is). Also, it gets to be a problem if you aren't very good w/ topping off. However, it is supposed to be better for true surface skimming. As for making the teeth able to handle more flow..the easiest is probably drilling out holes in the bottom of every other slot. But no matter how you do it, you're going to end up with acrylic shavings in your tank. Thankfully they float.

[crstjohn]

All advice is very good. For the drain line noise, hopefully you have a valve in between your tank and sump. Throttle the valve a little bit (close it) until you are filling the pipe completely before draining but not raising the level in you OF boxes. A flat weir definately increases the chances of livestock overflowing into the box but I have not had too many problems. In about 6 months I've had one fish (clown), 3 shrimp (the mantis took the ride twice) and a couple of hermits get into the OF. To get the fish out, I just closed the OF valve until the box filled and he just swam out. The shrimp actually made it all the way through the skimmer and found them in the sump. All have survived. Ideally, you want to skim the thinest layer possible off the top of the water surface. The only way to do this would be to use a weir the entire length of the tank or to use a closed loop system for circulation with a retrun pump that is sized to pump only enough flow to barely crest the weir. This system would definately require an auto top off as maintaining a constant water level would be critical. I did not use a CL system (doh!) and currently about 1/2" of water tops my weir which has about 9" total length. Jeff- stop by sometime and check out my setup. I'm in PQ.