What a relief! Now keep that jug of muriatic acid handy and blop some in now and again, and check your pH. Im doing that all the time right now. I used to get all "omg my pH is high!!!". Now Im just, oops, pH went up, blop blop.
Muriatic acid in the garage might not be the best idea. That stuff is so nasty that even it's FUMES can do some nasty stuff to metal. We saw a picture of a metal cabinet they stored an UNOPENED bottle of m.a. in it. The side of the door and all around where the UNOPENED bottle was rusted!!
I keep mine in a vented plastic bucket outside behind my barn where my critters do not go.
I would spray it down and give it a good brushing with the broom also being wet and see what happens.
I'm not sure how or what the tube does but since it has a mesh screen we can agree there shouldn't be any dirt in there. Make sure that's taken care of before reassembling it.I didn't use a broom yet, but did spray it down twice with the jet setting, and it helped. I can see it's still discolored and there are areas that are definitely stained with what look like smaller "droplet" shapes. I will wet down and scrub with a broom tomorrow.
We also cleaned our filter for the first time and saw that there was no air relief tube or air relief valve screen on the manifold, and let the warranty manager know. He was going to reimburse me for buying one. The hole where the tube goes on the manifold was clogged with dirt. I thought they just didn't install it at all, but later found it sitting on the bottom of the filter container. So it probably wasn't on there, ever, and fell off during installation.
It's official.
I hate pH, and pH hates me.
Our battle is now a daily thing. And I've even been adding MA twice a day to keep it within range.
I am also starting to keep a log of water depth from top of our waterline tile. I sense we could be losing some water but I am not 100% sure yet.
It is normal to lose a little, over time, right? But not much, and over a long period? Or?
What range are you keeping your pH? What pH does it get to when you add acid?
Sounds like normal Evaporation of Pool Water - Further Reading