Our private swim club has a 100% new water this spring. We have a ~55,000 gal in-ground pool w/ a NEW vinyl liner (thus the water replacement last fall). The pool was built in 1964. The pool was shocked last fall before closing -- I don't remember the chlorine level. The club (a co-op) will be opening the pool this weekend to prepare for Memorial Day swimming. We must pass township inspections for chemistry (chlorine, coliforms, electrical, etc.) the week prior. I am the CPO (Certified Pool Operator) and have taken the course on-line to become a CPO and I am a chemical engineer by training so chemistry isn't new to me. I was the CPO last year but things were pretty much "normal" and I got tips from the former CPO. With the water replacement and not having a commercial company doing the opening, I am sweating getting the chemistry right for swimming and thus opening. We have a DE filter w/ an erosion feeder and we are using tri-chlor tabs. We have a full Taylor DPD test kit (which I am familiar with) except the tube to read CYA (don't ask me where it went and I'm not sure I can replace just the tube - suggestions). All testing chems were stored in my basement for the winter. We don't have a high bather load (many times we are the only family there). Membership is restricted to 40 families.

How do I start this process? I am planning to pull a sample of the water from under the cover tomorrow or at latest Saturday AM and test it myself and also take to pool store for testing. I will also inventory chemicals. I have shock, tri-chlor tabs, and baking soda (I think) in hand from last year. Typically we have consumed a fair amount of baking soda (low pH - 6.8 -7.0 range) and last year chlorine ran high all season. The pool rarely if ever has used sodium hypochlorite although we have it in the chem shed. I doubt there is any CYA in the pool b/c of the refill. I had the supply water tested (well) before filling last year and iron and copper are fine (low).

Should I shock before addressing the pH? What level should I shock to? During the season we shock once a week at a set amount (member family does each Sunday night b/c bather load is low on Mondays). After shock and pH, address CYA? What if there is a lot of algae (have had both black and green algae in the past).

We have a large crew on Saturday to pull the cover (25' x 50'), reassemble pump (new last year -- anti-suction and very touchy to air), clean and reassemble filter, in addition to a myriad of other tasks. Vacuuming will be done 2-3 times a week until guards start at the end of June. A log of any chemistry adjustments (or changes to the erosion feeder) is kept at the pool. Because of the timing of opening (two weeks), I would like to have what I need on-hand to eliminate trips to buy chemicals (or the grocery/Sams Club for baking soda). I'll be running to the pool enough. The pump will probably get started up late Saturday or early Sunday depending on how long it takes to get the water level up.

I am new to this forum but I learned a lot of practical advice from it last year and this is my first post.

Thanks in advance!