I'm not getting enough suction to vacuum my gunnite pool.?

Question

I suspect a clog in the line and have vacuumed and run pressurized water through the line, but I have been unable to dislodge anything. I can't get my snake all the way through the line.

Answer 1

Your not being able to get a snake through is not surprising. Normally you wouldn't make it past the 90 under the skimmer. Too much change in direction in a 1 1/2 inch pipe for a snake to negotiate, not to mention the fittings being in the way.
You actually need to post a little more info. Do you see air out the returns when vaccing? What's your pressure like, before hooking up the vac? Is it normal? Have you vacced up pine needles lately, or anything similar in size and shape? The jam up impellors when they get past the pump basket and boy do they get by pump baskets. Have you had the line pressure tested?
Get back with that info and I can help some. Until then, it could be anything.

Answer 2

I don't know what type of vacuum your pool uses. There are two kinds that I'm familiar with. On my pool, I use a "kreepy Krawler" which attaches to the skimmer suction. I have found that it will stop working when the hose gets hairline cracks in it. These cracks can do two things....they can leak air into the system whice causes the pump to lose suction. Or they can suck in water which bypasses the vacuum head. You can check the hose for leaks by lifting it out of the water with the pump and vacuum running. You will hear air leaking in if there are cracks in the line.

Most hoses for pool vacuums are polyethylene or polypropylene, both of which will crack due to chlorine attack. If you keep your chlorine level high, they will typically last only a single season.

One other thing to check is to make sure your pool pump is not leaking air into the system. the seal between the motor and pump will eventually wear out, and you will get air into your pump and lose suction. You can see this if the discharge pressure on the pump is very low.