Blocked swimming pool solar heating panels


New member
Oct 12, 2020
I have an 8 battery roof solar heating system for my swimming pool which has suddenly has become completely blocked with no flow.
This may have been preceeded by the use of flocculant which then passed through my poorly maintained sand filiter, which in spite of repeated suctionng and backwashing, still resulted in a significant residue resettling in the pool
The sand has now been changed to a glass based material, and refiltration has completely stopped this problem- pool noe crystal clear.
I have now become aware of the possibility of "flocculant clumping", and wondered if a very large ammount of this clumped flocculant may have indeed been pumped up to and blocked the fine cappilary tubes in the solar panels.
Has anyone else heard of such a problem and what advice or suggestions are there to clear od dissolve these clumps?
Presumably they mainly consist aluminium sulphate combined with pool residue and proteinacious alge.


Gold Supporter
TFP Guide
Nov 12, 2017
Central California
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Oh, no. Sorry that's happened. I'd be tempted to try and backwash the panels, maybe by temporarily replumbing the system to get water to flow the other way. But something tells me that could make matters worse. So maybe that's a last resort.

@JoyfulNoise, is there a chemical solution for this?

Rocket J Squirrel

Silver Supporter
Bronze Supporter
Jun 7, 2018
Alamo, CA
Pool Size
Liquid Chlorine
My solar has 2 hose bibbs, one high and one low, which get opened only for draining the system in winter. If you have those, try attaching a garden hose with both valves open and blast clean water through the panels. If one direction doesn't work, try the other.