Copper introduced by PT lumber sawdust?

[HappyAuer]

I'm a newbie, so please let me know if another forum would be more appropriate for this question.

My AGP was installed less than 2 weeks ago. Construction of my pool deck began immediately afterward. The deck will cover the top rails; this design has resulted in a fair amount of sawdust in the pool. The solar cover has helped me keep some of it out, but I've vacuumed several times and mostly what I'm cleaning up is sawdust.

The deck frame is pressure-treated lumber. I don't know the exact treatment, but I believe most PT lumber is treated with copper compounds. I believe I've read here that high copper levels can cause staining. Does anyone know if sawdust will raise copper levels, and could it raise them enough to put me at risk for staining?

Should I vacuum to waste until the deck construction is done? I haven't thus far, so the sawdust has sat in my filter for days at a time. I backwashed the filter last weekend, but I've been generally avoiding backwashing because I'm trying to raise CYA (added 1/2 of my target dose after filling the pool, waited a week, backwashed, then added the other 1/2 of the dose).

Any thoughts on how serious a problem the sawdust is, and suggestions to handle it differently than I have been will be most appreciated.

Thanks!

 

[chem geek]

Unless you added the CYA directly to the skimmer, you shouldn't need to worry about backwashing. If you added your CYA to a sock over a return or in a sock or T-shirt in the skimmer, then it should be dissolved in the water rather than caught in the filter.

 

[zea3]

You can have a sample of the water checked for copper, to give you a little peace of mind.

 

[phonedave]

Copper does leach out of pressure treated wood (even the "new" non-CCA stuff)

I can't tell you how much, or how it will effect your pool. Keeping your water balanced (pH, TA, etc all are recommended levels) will help to mitigate staining. If you really are that worried, you can add a sequestering agent just to be sure.

Me, I would vaccum to waste, and then when the deck is done, backwash. CCA is not that hard to add, and if it goes low, it really is not an issue - you will just burn more chlorine until you get the level back up. I would that more for the fact I dont want sawdust in my filter, not because of the copper.

-dave

 

[HappyAuer]

Thanks for the helpful advice. I suppose I'd prefer to vacuum through the filter and then backwash as opposed to vacuuming to waste, because it takes me more than a few minutes to vacuum without having a deck to stand on yet, and I'd lose a lot of water running to waste for that long. I tested CYA today and got 30, which should mean it's almost fully dissolved anyway (target was 35). Dave, you make a good point that adding CYA is easy and would be preferable to tolerating sawdust in my filter.

I like the idea of having a sample tested for copper. I'd rather do that before adding a sequestering agent. Is that a test available at most pool stores? And are their results generally reliable, or would I be better off getting a test I can use at home?

 

[minimonster17]

I don't know if this helps or not, but here I go... If the lumber came from Lowe's it definitely was treated with copper. Lowe's, among several other chain lumberyards use a treatement chemical called ACQ. It stands for alkaline copper quaternary. The stuff is not toxic to people, but is extremely corrosive to steel. (This is why deck joist ties and deck screws cost so much, they have to put so much **** zinc on them to prevent oxidation.) Forget the old CCA stuff someone else mentioned, that was the arsenic base. This comes from my background of being in the lumber business for ten years.

 

[HappyAuer]

Thanks, minimonster17. The PT lumber in my deck has markings indicating the treatment was ACQ. I wondered if it was toxic as I swam around with my eyes open during the deck framing phase. Thanks for easing my mind about that. Hopefully I cleaned it all out of the system before any steel parts could be affected.