Tips on Treating Algae in a Pool
Keeping a pool blue can be more challenging than people may think. Problems arise last minute and can cause your pool to go from a blue to a swampy green. Good news is, algae is usually easy to get rid of, though black algae can be very difficult if it starts growing in a pool and spreads. But again, don’t worry, I will provide you with tips on treating algae in a pool and getting everything cleared and ready to safely enjoy.
This is the most common type of algae, it usually brushes or even wipes off of the pool service with ease. This type of algae is easy to attract, it can sprout in less than a day leaving a mustard yellow or green color on the walls, floor, and everywhere else. Which is why it is important to Follow these steps in order to get rid of the algae properly.
Step 1 – Brush pool vigorously and get every corner and surface of the pool. This is going to let the chlorine/chemicals do their job better and faster.
Step 2 – Get a shock of your choice, I wouldn’t use any cheap low quality stuff! We use a strong concentrated Cal-Hypo shock on our pool service route. Cal-Hypo is a granular chlorine shock that makes it easy to handle, but keep in mind it can be explosive if near or comes into contact with Tri-chlor or tabs containing tri-chlor. Cal-hypo shock will increase calcium because that is the main ingrediant, you may want to try a Tri-chlor shock instead if your pool is high on calcium. The proper range should be 250-500ppm. Tri-chlor shock increases CYA/stabilizer. So you want to be sure you won’t be adding to something if your pool is already high. High stabilizer will reduce the effectiveness of chlorine. Both types of pool shock will affect your chemistry, mainly if the shock used for extended periods.
It is very important to watch your chemical numbers closely. If you want to rid the algae without those two types of shocking agents, and not add to your other chemistry such as calcium or CYA, use 10.5% or 12.5% liquid chlorine. Liquid chlorine won’t add undesirable chemicals except chlorine. Keep in mind, most shocks and chlorine raise the pH level. It is important to adjust the pH level down by adding some acid, reduce the pH to about a 7.0-7.2 for the best effect. Chlorine works best at sanitizing when at a lower pH. If the pool is say, 10,000 gallons, you may add something like 2 or 3 full 2.5 gallon chlorine. If using dry chlorine shock, add the recommended dosage, doubling down on the dose is sometimes needed depending on the severity of mustard algae growth. After adding the shock let it circulate for around 10 minutes with the pump on. Then add a Sodium Bromide algaecide. We use No Mor Problems. Add the dosage it recommends, doubling down won’t hurt.
Step 3 – After waiting at least 24 hours, recheck your chemicals. Adjust your chemicals as needed back into their proper ranges, to bring PH down use muriatic acid, to bring PH up use Sodium Bicarbonate. Also make sure your CYA is in a good range, 40-80ppm is a good range. Anything above or below that, chlorine will not work effectively or won’t hold, which can also lead to algae issues.
If you need to use a dosage calculator check out https://www.hayward-pool.com/shop/en/pools/water-chemistry-calculator.
One more important note, check your phosphates in the pool. High phosphate levels in a pool can lead to algae battles that won’t seem to stop. Phosphate level in a pool should be closest to 0ppb as possible, but from experience anything under 300ppb will not usually cause any noticeable problems. Especially if you maintain your chemical balance and shock or use algaecide regularly.
Step 4 – Clean your filter or backwash, algae has now been filtered into it and is probably dirty as well. You may pull out a nasty green filter, clean with high pressure nozzle on a garden hose if it is a cartridge filter. If it is a D.E. filter, backwash it and recharge it with the proper amount of D.E. via skimmer. Most filters have the D.E. amount on the label. Most require 4-8lbs of D.E., but make sure NOT TO BREATH IT. If your pool has dead algae on floor, just vacuum up and re-clean filter after.
Step 5 – Pool should look good at this point if all was done right. If not, repeat the steps again one more time. If it has cleared up very little, you may want to contact a pool professional to take a look. Many things can cause problems in a pool. Leaks can cause your pool not to hold chemical, which just ends you up with algae. If you suspect you are loosing more than an two inches in a week or so, contact a leak detection company, you most likely have a leak.
The most resilient and difficult type of algae to get rid of. Are you brushing your pool and it still won’t come up? If they are really dark green or black looking spots covering your pool, you have black algae. Here is a guide to killing black algae in a pool.
Step 1: Buy a wire pool brush, you need to scrub the heads off of the black algae to expose the root system so chlorine can effectively kill it. Scrub the black algae infected areas good until you see it lighten up a little or it will kind of smear. It might not be that noticeable but if you scrub it good then you can be confident you did it right and the root system is exposed.
Step 2: Buy some granulated tri-chlor, cal-hypo can work, but try-chlor seems to work better with black algae in my experience. this is the most effective way to really hit black algae hard. Get get 4-6lbs, maybe more depending on pool size. Also bring the pH down temporary to about 6.8 or 7.0. After you have scrubbed the pool down, evenly sprinkle the tri-chlor all over the pool and as much as possible directly on top of the black algae as you can. Let pool run for 24 hours.
Step 3: Check pool chemicals and balance as needed, as pool should be clear of the black algae, in some cases there may still be a little, if so just brush them once more, then sprinkle a little more tri-chlor on top of the remaining black algae.
Step 4: Enjoy your blue algae free pool!