Applied Biochemists 406303A Black Algaetrine Swimming Pool Algaecide & Deposit Control, 32 fl oz, White

The first bottle the seller sent leaked out few oz in the box. Told the seller about it and they sent a whole new bottle. Great service; I highly recommend this seller! As for working miraculously on black algae (as some reviewers had written), the jury is still out. I have a 30' above ground pool and I followed all the instructions; even used double doses. After 3 weeks the back spots (black algae) were still there. They may have been diminished some but it wasn't noticeable so I got in with a nylon pot and pan scrubber (they look like a nylon version of steel wool) and scrubbed all of the spots off with my feet using those scrubbers. The nylon pot/pan scrubbers work great and won't harm your vinyl pool liner; the only way to go. I did notice that after the application of this stuff though, the algae did come off a lot easier and has stayed gone so far (knock on wood). Bottom line is that with the heavy infestation of black algae that we had, this product did not make it vanish over night... or even within 3 weeks (even after brushing it twice a day every day). Those reviewers who did say that this product made their black algae vanish over night or in days were either delusional or did NOT actually have black algae.

After returning home after a long absence, I found that my chlorinator and pump had stopped working and I had a pool full of green and black algae. I started treatment with my usual green/black agaecide which killed the green algae, cleared the water, and got rid of most, but not all of the black algae that had formed on the bottom of the pool. The pool is gunite/pebblecrete which makes it more difficult to remove black algae. After several weeks of brushing and vacuuming, the bottom of the pool was improving but just marginally. I decided to try this algaecide to see if it could totally eliminate what looked like huge stained areas of the pool bottom. This algaecide is a totally different formula than my previous one, and unlike the other one, does not require super-chorination (shocking) of the pool when using. I used half the bottle in my 11.000 gallon pool in each of 2 applications a couple of weeks apart. It seems like it continues to work for 2-3 weeks after application, as every few days for several weeks I noticed the dark areas getting lighter. The key is being patient and brushing with a stainless steel brush every few days. After 2-1/2 months, the dark areas are almost completely gone and the bottom of my pool is back to the Caribbean Blue it's supposed to be.

I have learned since moving into a house with a pool over 25 years ago to get ahead of any algae bloom. If persistent brushing, keeping the chemicals perfect, and 24/7 running the pool doesn't work - this is the ONLY product I have found that will actually get you back to a sparkling pool. Pretty darn pricey though so believe me I try everything before I go to the Black Algaetrine and always have a bottle in the shed. A 38,000 gallon pool usually only takes one bottle - but I don't let it get emerald green in the first place.

This product along with "Pool Essentials 25556ESS Shock Treatment" wiped out the black spot algae in our swinging pool. I applied the granular shock with the pumps off in a uniform manner around the pool trying to spread it as evenly as possible. I let the shock set for a couple of hours and then applied the "406303A Black Algaetrine" and kicked the pump on. The Algae had all died within 24 hours. Of note, I have tried to use just the shock and it will kill black algae by itself, but it near impossible to get all of it. I would recommend for maintenance or if you catch the black algae early enough that you may try just the shock, but the combo of the two products wiped it all out in one application and I have been dealing with it for over a year. The only reason I am not giving it a 5 star rating is that it caused my pool to be cloudy for about 2 days after treatment when the pumps were running. When the pump was not running the pool would clear up, but would cloud up as soon as it kicked back on. So it was probably more of an aeration of the water than cloudiness.

406303A Black Algaetrine Swimming Pool Algaecide & Deposit Control, 32 fl oz, White Ruined my pool! I've used this product before with good results. This time it stained my pool SEVERELY! Applied following the directions. SEVERELY stained my pool. Tried shocking the stains with chlorine and scrubbing. Looks like it ruined my gunite pool. I would like a full refund. I already threw away the empty bottle, as there are no returns for this product. Maybe you can pay for my replaster too.

When you get the are to kill black algae there is not much you can do to kill it. I love other products from this company and this is no different if took a while to work but it did great!

This product worked great, on my black algae spots that were growing on the floor of my pool. Almost completely gone with the first application. Absolutely gone upon the second application. And you can swim after each application. I highly recommend it for black algae.

Great product..hot summer pool days just around the corner.