A fair number of the pools that we convert to Pooled Energy are green when we arrive. The owners have given up on the unending task of manually keeping the water clear. Combined with a scientific understanding of what makes your pool go green and a bit of practice we’ve perfected our method for fixing green pools.
Here’s our step by step guide. With good measurements and the right chemical volumes we can reliably “dose” a pool and walk away with confidence that it will come good. The only intervention is a bit of back washing to clear the flocculant from the filter, read on.
1. Set the pump running
We’ll need to move the water continuously for the next 24 hours or so. Both to mix the chemicals we’ll be adding and remove the dead algae.
2. Add chlorine
We give the pool a big dose of chlorine (super-chlorination is the industry term). This kills the algae that are making the pool green.
3. Correct the pH
The wrong pH rapidly reduces the effectiveness of chlorine. Take a measurement and add acid to lower the pH or alkali to increase the pH to bring it within the optimum range.
4. Check cynauric acid
Commonly known as a stabliser, unlike chlorine it is persistent in pool water. It’s only diluted by water changes (draining and toping up). Too much cynauric acid locks up too much of the chlorine stoping it from killing the algae. We check the level and reduce through water changes if it’s too high.
5. Clarifier / flocculant
With a good dose of chlorine and corrected pH the algae will be killed, being bleached in the process. This leaves less green but cloudier water from all the dead bleached algae. To remove them we use a flocculant that makes them clump together so that the filter can remove them from the water.
The dead algae now trapped in the filter needs to be removed to keep it working efficiently. You need to periodically backwash the filter (say 2-3 times per 24 hours depending on how much algae there is) to send it to waste.
7. Slow release flocculant
A really green pool contains a large amount of algae. We need to get rid of all of it. To help with the task add a slow release flocculant tablet to the skimmer box.
8. Phosphate level test
Lastly we test the phosphate levels in the water. Phosphate is a fertiliser that will promote the growth of algae. It can enter the water from garden run off and bird droppings. If the levels are too high it could be contributing to the algae problem. To treat was use a phosphate remover (commonly called starver).
It is, and keep in mind this a general guide only. If a pool is going green on a recurring basis there’s likely to be a root cause that warrants investigation.
Let’s face it, even once you know how to fix your green swimming pool there are better things to do with your weekend and things to spend money on than pool chemicals. Sign up for the Pooled Energy system and a) your pool won’t go green in the first place, b) in the extremely improbable event that it did (never say never), our monitoring would alert us and we’d send someone to fix it – free of charge.