mogurnda said:
That's right. So far, my drain and return have never come out on their own, but I suppose it could happen.
When I drain the tank, I'll make extra-sure that the pipes are firmly fitted into the bulkheads.
I hate to suggest it, but you might think about lowering the level of your baffles.
You are probably right. Chalk it up to a beginner's mistake... I was shooting to utilize as much of the space in the sump as possible (for increased water volume) and also wanted to have a good capacity for the return section (though I ended up making the skimmer section a little bigger than planned, to give myself some wiggle room). However, I think making the baffles so high may have been counterproductive at worst, or simply without much benefit at best. Though it does provide the maximum possible water volume in the skimmer section, when combined with having to keep the return section half empty, it's probably a wash. I may in fact be better off with lower baffles, more water in the return section, and let the "empty" space above the baffles serve as my power-off overflow buffer.
I didn't notice whether the skimmer was running during your power-off test, but that will add a few more gallons to the sump as well.
Yes and no. I did run it and shut it off along with the other stuff, but now that I'm thinking about it, that probably does not give a completely accurate picture of the situation. Right now, the skimmer is just sitting full-depth in the sump, but I will be elevating it on a platform. I assume when I do that, more water will be contained in the body of the skimmer (in other words, the same amount of water that is in the skimmer section of the sump and uppermost portion of the skimmer now when it is running, PLUS a little additional water for the part of the skimmer that will be elevated above the waterline).
You might be able to deal with the bubbles from the fuge by slipping a piece of 2" PVC pipe over the fuge drain pipe in the return section. It would act as a simple bubble trap.
That's a good idea! So, if I understand you correctly, I'd let the drain pipe dump into the larger pipe with, I presume, a cap on the bottom to force the water to come out at the top, and have the top of the larger pipe a little above the waterline (so that the water spills out of the pipe in the same manner as it does when spilling over a baffle)?
Another possibility is to use a tee rather than an elbow on the 90 degree turn of the drain. It may allow more air to escape and reduce the problem.
Again, just to make sure I'm following you, you're suggesting a tee with the open end sticking up, with the hopes that some of the air exits through this opening instead of being carried down into the water?
This may or may not be possible. It's a little hard to see in this photo, but the last fitting is not a 90, but rather a 45. I used a 90 coming off the union to shift the drain closer to the corner of the refugium, then finished off wtih another 90 (at an angle) and a 45.
I could simplify this by going straight down into the refugium with the tee directly from the union (and not having that little jog towards the corner). Or, I wonder if I could drill a hole in the top of one of the existing fittings to accomplish the venting.
I went ahead and added a couple of new bulkheads to an existing order of stuff, so I'll have them on hand if these other things don't work out.
In other news, I think the flow problem from the drain has been solved. As mentioned above, I had to place considerable flow through the refugium to keep the overflow box happy. I did some reading on the official Durso standpipe page, and discovered that the problem was a result of the final piece of PVC that dumps into the skimmer section. I had it going deep into the sump, ending only a couple of inches from the bottom. Durso says that this causes backpressure in the drain line due to trapped air desperately trying to work its way back up the pipe, eventually "burping" it out, then doing it again and again. I cut the pipe so that it only extends down a few inches past the surface, and now I can totally cut off the flow to the refugium and still keep the overflow from doing the toilet flush thing.
This, however, has revealed (or caused) another issue. Now, the skimmer section looks (and sounds) like a big pot of boiling water due to the big bubbles. I don't think it was that bad when I had the pipe going down further (maybe it's because the flow is higher now, and/or because more of the trapped air is actually making it out of this pipe now, as opposed to before when much of it would travel back up and be burped out).
I wonder if perhaps your idea of adding some way for the air to escape before it hits the refugium water would also do some good here.
"Is it always going to be this loud?" (comment from my wife). In all honesty, I don't think it's that bad... the little FW tank (which has a HOB filter and a bubble wand) seems noisier to me. With the 90g, I hear a little bit of splashing noise from water flowing into the overflow box, a gentle chorus of hums from the powerheads and pumps, and the above mentioned boiling water sound from the drain dumping into the sump (the only thing, to me, that stands out).
--Mike