How to add chemicals to newly filled pool?

AussiePossum

We have emptied our above ground pool and are refilling it. We have never owned a pool before. We have a bottle of chlorine and packs of flocculant and super shock. Please could someone advise what other chemicals are needed and what order to put them in? Thank you.

MitchellMc

Welcome to pool ownership @AussiePossum. It can feel a bit overwhelming at first, but you’re doing the right thing by asking before adding anything.

For a newly filled pool, you won’t need flocculant or SuperShock straight away. Flocculant is only used when the water is cloudy with fine sediment, as it binds particles together so they sink to the bottom to be vacuumed out. With fresh tap water, there’s usually very little sediment present, so there’s nothing for floc to do at this stage. SuperShock is generally used when chlorine levels have dropped very low and you’re dealing with algae, chloramines, or a contamination issue. A brand new fill doesn’t fall into that category, so it’s not something you need to add now either.

The only chemical you’re likely to need initially is chlorine, just to establish a sanitiser level in the water. The amount depends on the size of the pool, but even then it’s best not to guess. Rather than tipping in half a bottle or more and hoping for the best, the safest approach is to let the pool finish filling, run the pump to circulate the water, then take a clean water sample to your local Bunnings store. They should have a Hyclor testing machine, which provides clear guidance on the water's requirements, including chlorine, pH, alkalinity, and any other parameters that may be out of balance. It would be worth giving them a quick call before hand to ensure they have the machine in-store.

On a fresh fill from mains water, the test may show that chlorine is low or zero, pH may be slightly high or low, and alkalinity may need adjusting. That’s all very normal and easy to correct once you know the numbers. What’s best avoided is adding multiple chemicals blindly, as that can actually make balancing the water harder and lead to more problems down the track.

So for now, focus on filling the pool, circulating the water, and getting it tested. Once you understand what the test results mean, maintaining the pool becomes much more straightforward and a lot less intimidating.

Here's a helpful guide: How to maintain a pool.

Please let me know if you have any questions.

Mitchell