Return lines have no pressure. Plus a thought...


Mar 23, 2010
I have an inground 15k gal pool that was a massive mess before I bought the house. After some trial and error, losing a fight with the algae, massive chlorine demand and stains in the plaster I just couldn't get rid of, i decided to bite the bullet, drain, acid wash, prime, paint and refill. Took about a week and a half and 2 very good friends :) Well, needless to say, the pool looks fantastic!
With one exception...

The return lines have virtually no pressure. I have a cart filter that doesn't get cleaned too much because there's an Aquabot T-Jet in the pool, running most 8-9 hours a day that keeps the pool nice and clean. But regardless of me cleaning the filter or not, there is no pressure in the return lines. I put my hand there and I barely feel anything. With filter in, the pressure inside the filter is about 30-35 PSI. I suspected there was something stuck in the lines so I removed the cartridge and ran the pump. Pressure inside, 15 PSI. Water jetting out of the return lines like mad. So the pump is working, and the lines appear to be clear. cleaned the cart, put it back in, same 30-35 PSI, same water flow as before. Short of spending 100 bucks in a new cart, what could my issue be?

Which now brings up a thought ... and don't shoot me for it, i'm new :)
My Aquabot does a very nice job at cleaning up. I have an amazingly clean pool. I skim manually most every day, 10 minutes or so of pole in hand doesn't kill me. I've dumped some 8 bags of salt in the pool, using SolarChlor for chlorination small bag of shock every 2 weeks or so, some liquid chlorine when needed. So, now, the way I see it, the job of the pump is to circulate the water. Filter catches the bad stuff and so on. However my Aquabot does essentially the same thing. It is rated to move some 5k gallons of water an hour. Well, that's a little extreme I think more like 2000 is an easier swallowed number. But if it's doing all the water moving for me inside the pool, at a fraction of the cost of the pump, while at the same time cleaning up all of my nastiness, what exactly is the point of having a pump? I could buy a second Aquabot, stick it in the pool doubling the cleaning capacity as well as the water movement. Am I far of the mark here? I don't know...


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Pool robots are not rated for daily use. They are designed to be used say once a week for three or four years. If you run them every day they will wear out far more quickly, and are rather more expensive to replace than it costs to run most pumps.

You might just need a through cartridge cleaning. See this post for the full cleaning procedure.

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
SouthWest Alabama
Your aquabot, even though a good cleaner, is not designed to filter the water like your cartridge filter does.

From your description the cartridge is the issue. You could try a chemical cleaning but if your filters are very old you should just get a new set.

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