Inspired to gravity feed.....

[HoopsGuru]

I've read both your BoCP and the newest Reef Invertebrates, and wow they make one want to expand their experience and systems!

I've since determined I wanted to confront all my fears of plumbing, and dive into drilling a tank and setting up a gravity fed refugium for my 55g display tank. I sweated through using a Dremel on my 16g tank (twice for two bulkheads!) and got to know the PVC aisles in HD and Lowe's quite well. I confidentally put everything together and......


Problem:eek1: ....Bubbles, bubbles, bubbles!

Here is the thread I started before realizing I would like to go right to the source of someone who has probably seen a variety of such setups. I was going to email, but perhaps a link to the thread I started here can catch you up to speed enough to potentially provide some opinions:

http://reefcentral.com/forums/showthread.php?s=&threadid=428190

A quick summary of the fuge: 16g tank with a 3/4" drain and 1/2" return. It sits on its own stand above my 55g display. An elbow and strainer (pictured in the thread) set the water level and a durso mod (PVC "T" capped with a small hole in it) keeps the drain from slurping air through the fitting in the tank. A maxi-jet 900 returns water the short distance back to the 16g fuge.

The only problem is that I have a ton of bubbles coming out of the output into the display tank (and the resulting moisture and salt creep all over the place). Is there any way to bleed the air out before it gets to the output? How do people have gravity fed refugiums and avoid this problem?

Any insight would be greatly appreciated.

 

[Anthony Calfo]

the short answer would be that I suspect this overflow is being slightly overdriven. That would cause the slurping sounds and/or the bubbles. Do check to see what your overflow hole size is rated at (bulkhead mfg website) and compare that to the pump flow. For example, a 1" bulkhead may be able to handle 500-600 gph max... but at a noisy siphon/flow... and really best runs at 300 gph max. Having undersized drain/overflow holes is very common indeed. Food for thought

Anthony

PS- thanks for the kind words about my/our books... truly a labor of love

 

[HoopsGuru]

Thanks for the food...chewing away here

I dropped the pump down to a Maxi-jet 600 this morning. According to the head loss calculator here I am running about 122gph through a 3/4" bulkhead rated at about 300gph max flow.

This would fall more into the range you described above so I will experiment with it. The slurping increased, even as I drilled the hole in the Durso cap larger......so, I deduce something else is involved now as well.

Forgive me as I now get longwinded trying to be thorough.

My interpretation of your statements above is that a gravity feed, not overdriven, should not have an issue with slurping or bubbles. IOW, a Durso mod should not even be necessary? I am considering removing the Durso (familiar T with cap and hole drilled in) since it requires me to use an extra elbow on the drain to route it over to the display tank....probably reducing the available gph capacity.

My original drain looked like this:

Should this be all that is required for a nice/silent gravity feed system?

 

[Anthony Calfo]

correct... the Durso adaption is an excellent solution for the common problem of noisy/overdriven/misplumbed overflows... but it should not be necessary with soft runs and adeqaute drainage (many of my friends are quite familiar with my peeve/rants about undersized overflows and/or so-called "reef-ready" commercial tanks that are anything but <G>). To be clear, I think the Durso standpipe is an excellent solution for many. But I have installed hundred of quiet systems through the years (and never a dreadfully noisy one) without the need for modification. It really gets back to proper plumbing (simple, soft runs) and adequate marriage of pump size and overflopw capacity.

Its all still speculation though here for me/us. From a few images and mostly text messages, the problem is tough to diagnose definitively. If you have a local or regional aquarium society, the fellowship pays off handsomely in cases like this. Do seek some local experienced or professional aquarists too for a visit to peep your system in person. Aquarium service folks that have been the biz for many years are a good option too

best of luck!

Anthony

 

[HoopsGuru]

Thanks for your time Anthony, I was just hoping that with the extensive DIY & fuge experience that inspired your books...you might indeed easily spot any glaring mistakes (For example, i should ot be using an elbow without a overflow box, etc). I think we've reached that point of understanding.:thumbsup:

I have plenty of PVC left over to experiment, which is one of the best tools for learning. And I also have larger bulkheads I purchased for future use that I can grind out more glass and install since a larger drain cannot do anything but good.

Cheers!

 

[BlueCorn]

Not to hijack the thread, but HoopsGuru, when I put my gravity fed fuge in I had a bubble problem in the return as well. What fixed it for me was angling the return pipe somewhat to slow the flow a little:

Hope that helps - cheers.