big skimmer bubbles

[DMBillies]

I have an ASM G1-X. It used to have the stock output with the riser tube and sponge. I hate this because it causes a good bit of salt creep and the sponge gets nasty. Not to mention it isn't very consistent. I have every intention of fixing it.

I saw an idea that I thought would work so I tried it out. I just took a T, put it on the riser tube. On top of the T I put a PVC cap. On the horizontal output of the T I ran a piece of PVC into a 90 degree elbow and that puts the water back down into the tank. The stock riser tube would let me control the height of the water in the skimmer. This is basically a cheap version of the gate valve mod because it avoids the gate valve. I figured I wouldn't get quite as much control, but I figured it would be good enough. The problem, which I should have foreseen, is that the water falling back into the tank is pushing air down with it and creating some big bubbles in the sump. Microbubbles aren't a problem, but over time these bigger bubbles are going to create a salt creep problem. I could put a filter sock on it, but part of the reason I am getting rid of the stock sponge set-up is that I don't want to have to clean something out all of the time.

I looked at the gate valve mod on my Euro-reef to figure out how it got around this problem and I see that the sump water level is actually at the same level as the gate valve. So, once water clears the gate valve it isn't falling back into the tank from any kind of height, thus no bubbles.

I looked at creating a similar situation with the ASM, but the way it is designed, if I put the gate valve on the horizontal part of the "loop" as my euro-reef is, it is going to have to be at least 3-4" above the water surface. The ASM output blocks me from putting the T and lower.

Putting the gate valve on will slow the water and fill the plumping up before the valve, but the water will still free flow after the gate valve. Therefore, I think I'll have the same issue even if I do put a gate valve in. Is that right? On the other hand, I might think that eventually a lot of the bubbles would get pushed out of the plumbing after the gate valve and because it will be sealed from air on both ends (gate valve on one end and tank water on the other) the bubbles would stop. I'm not sure really sure about that.

I'd love any thoughts on this...

 

[DMBillies]

The thought I had is to put the gate valve on the down spout. This wouldn't be ideal in terms of space savings, but I'm pretty sure that would fix the issue. Just don't want to do it that way if I don't have to.

 

[crumbletop]

OK Brian. The word picture isn't helping me too much. If you want to reduce bubbles / splashing, one thing you could try is letting the side of the T empty out onto a piece of flat acrylic or a large diameter pipe that is slanted back into the tank. This would let the water roll down hill into the sump, rather than fall and splash. I'm just making this up as I go along, but maybe there is a good idea in there somewhere

My bet is the large diameter pipe would work well, especially if you submerged the end under water a couple of inches. This would let any bubbles rise and keep them within the pipe, while the water escapes out the bottom.

 

[DMBillies]

Ok, so I should have put a picture to start with.

Option 1 (kinda): This is the mod depicted in the picture. They have the gate valve on the "uphill" side just after the water leaves the skimmer. Although this mod would work for most skimmers, I'm very confused about why they bother with a T just past the gate valve instead of simply putting in an elbow (it is seemingly possible that some microbubbles could escape there, but I'm not convinced much would happen...anyway, I digress). In this case, the water goes across the horizontal and back down into the tank as a free fall (notice all of the bubbles on the surface of the water). This is not the mod I would consider the typical gate valve mod according to what I've seen. It also is not very elegant in solving the splashing problem (did I just imply a skimmer mod could be elegant...wow). In any case, this mod will definitely not work because I have a smaller skimmer model and wouldn't have space for the gate valve before the T without it making the rise too high and overflowing the skimmer.

Option 2: Put the gate valve on the horizontal part (after the T in the above picture) and lower the horizontal part down to the water surface level. You would also insert a riser tube into the T that is roughly the height of the skimmer. This is what I would consider typical. Here, the gate valve is used to put back pressure on the output and back water up into the riser tube. This would also increase the level in the skimmer. This method allows you to place the gate valve very close to the water surface (no bubbles), allows the gate valve to control the level of the water in the skimmer (and the riser tube), and if something gets stuck in the gate valve water will just overflow out of the riser tube instead of putting all of the pressure back into the skimmer (which, in option 1, would cause the skimmer to overflow spectacularly and re-release all of your skimmate back into the tank).

Here is where my question comes in. I cannot get my gate valve at the water surface with this set-up because the skimmer output is too high on the side of the skimmer (similar to the picture). So, there is still going to be some falling of water from after the gate valve down into the tank... unless, the fact that it will be sealed with water on both ends (gate valve and sump surface) will mean that eventually the majority of the air will work its way out of that pipe and stop blowing bubbles into the tank.

Option 3: Put the gate valve on the "downhill" leg of the pipes at the output. This has all of the benefits of option 2 and lets me get the gate valve closer to the water (little if any falling water). The problem is, then the gate valve is close to the water (almost all of them have at least 1 metal screw on them) and will be really hard to adjust because it will be inside of the my really tight sump.

Since the initial post I put a ball valve on end of the output. It's harder to adjust the skimmer level than a gate valve would be, but it works and I can totally submerge it because there's no metal parts.

And yet another novel... sorry

 

[crumbletop]

My suggestion is to try a larger diameter pipe after the last elbow -- actually, I think I'd make that elbow a T. Then I'd angle the T + the larger diameter pipe so that the water rolls down rather than splashes.