Weak Pump Or Crazy Physics?

I have a Air Pump labeled to work for up to 20 gallon tanks, and it's been working great for my 20g long tank with one airstone strip. I bought 3 more strips, one about a foot long, and the other 2 about 4 inches long to go in my 37g tank. I also bought a 2 output valve thing. Unfortunately the long one sucks and I broke it already, and the strips aren't linkable without buying those small splitter/valve things. I think I should have gone with the bubble wands =/

Anyway, the problem is that I can't seem to get the 4 inch stone (or the long one before I broke it) to work while its in a Horizontal position and laying on the floor of the tank. It only works in horizontal mode the first 3/4 of the tank from the top, and only works on the floor of the tank when vertical.

I realize the pump isn't designed to work like I'm trying to get it to work, but I would assume that if it was just a simple "pump not strong enough" problem the bubbles would still come out, it would just be weak and maybe not make it to the top. I also question if it's maybe a positioning/crazy physics problem because when its 4 inches from the bottom of the floor in the horizontal position the bubble flow is at full power. When it goes down the extra 4 inches to the floor of the tank it has 0 bubbles coming out.

andyjs said:

So is it still running on the 20 gallon and the 37 at the same time? If so, the water in the 37 is probably deeper, so it's harder for the air to get down there, so it's taking the easy way out and going out of the stone in the 20. When you lift the airstone in the 37 up to 3/4 of the way down, it's probably at about the same depth as the 20, so it works.

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I think you are right about it being the same height at 3/4 of the tank in the 37g and the bottom of the 20g tank. They are about 1 foot away from each other and the 3/4 line and bottom of the 20g line up perfectly. Guess I need a more powerful pump.

CWO4GUNNER said:

Cheap air pumps are a waste of money, I know because I have gone though about 6 in 6 months, thankful that most were free and part of a used tank purchase. When I say cheap I mean anything that is not a professional commercial air pimp because I have used most of the big LFS name brands and some huge looking pump. The problem is too many moving parts specifically the bellows and the plastic valves that have to open and close thousands of times per hour finally start to leak under back pressure, one minute their pumping air out the wand on the bottom of the tank beautifully, the next minutes they are barely working. I have switched all my tanks over to power heads specifically the AquaClear 402 using a pickup air tube to blast air against the back of the aquarium and O2 test readings over wands improved by 3 PPM, allot in dissolved O2 terms.

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I have the Whiper brand pump which gets pretty good reviews. I guess I could look into powerheads, but I really don't need more oxygen. I get pretty good surface water agitation, its more of a looks thing for me.

RodInCALIFORNIA said:

yup sounds like you pump has died mine do the same every now and then toss and replace.

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I think I described it wrong, there is nothin wrong with the pump. It still pumps perfectly fine into the 20g tank, and pumps at full power into the 37g tank at 3/4 of the way from the top at the same time as its pumping into the 20g. The pump it seems was not designed to work like I am trying to get it to work. It's not an issue of breaking down, its an issue of, you need a more powerful one.

SMinNC said:

How about 2 pumps instead of 1 more powerful.

I'm thinking you'll need alot more power to overcome the phisics thing. Because it'll still take the easiest way out, the 20g.

Try the one pump you have just running on the 37g. If it works, just get another of the same pump. And give each tank its own pump.

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I ended up getting the Whisper 100. Should be able to handle outputing to both tanks.

dundadundun said:

have you considered choking the output on the 20 by splitting it with a gang valve and closing the valve slightly? a second pump is really ideal for such a small pump though imo.

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Yes, I tried closing valve that goes to the 20g tank, and only outputting to the 37g, and that work. Then I opened the valve for the 20g and they can it worked, But I want to add three more Airstone in the 37, so I doubt it will work with 4 different stones total. I already made an order for the Whisper 100, so it should be able to handle both thanks, and if for some reason it doesn't I'll just use one pump per tank.