Killing Black Algae by Draining

[scleland]

My experience with Black Algae feels like what it must feel like to have Herpes. The little boogers keep flaring up and I don't think it will ever be possible to be cured... I live in fear awaiting the next outbreak. Like my analogous Herpes victim, I must accept some responsibility. Through promiscuity (or in my case, travelling out of town), I have on more occasions than I want to admit, let my FC drop to zero. The pool never turns to swamp; just a little cloudiness before I catch it and set it straight. This pattern of self-destruction began last summer.

Following the instructions well documented in this forum, I raised my FC last year and [visibly] eliminated the black algae last summer. They came back this year, and I am now zapping them again. I fear that they will return after this round. I hose off my cartridge filters, but I just feel like those little microscopic microbes are lurking somewhere in my system waiting for the opportunity to bloom again. So I am thinking of going nuclear on the little black algae boogers.

What if I just drain the pool at the end of this season, scrub it, sanitize it, and re-fill it? I haven't re-filled the pool in the 3 seasons since I put it in, so maybe I am due. If I do follow this strategy, is it indeed the equivalent of going nuclear? Will I finally be cured of black algae? Is it a sound strategy or just the result of an exasperated, black algae infested pool owner?

 

[scleland]

I should have taken some "before" pictures to garner a little bit more sympathy, but here are some mugshots of my little nemeses after a couple light scrubbings. Since I have PebbleTek (or PebbleSheen?), this algae can hide in the little crevices between the pebbles which makes them particularly difficult to eradicate. The spots on my baja step and benches are close enough to the surface that I can scrub them well, but the ones that are 6 feet down are very difficult to find after the first few scrubbings.
[attachment=0:1mc3dinp]BlackAlgae.jpg[/attachment:1mc3dinp]
Notice also the light brown discoloration in the grout. This is another reason I am thinking of just draining the whole darn thing and hitting with muriatic acid... my grout was discolored the first night it was plastered from a wind storm blowing sand from nearby construction into the pool. I've never been able to get that discoloration gone.

 

[JasonLion]

Draining most likely won't help anything. A few people have had success with pressure washing, which can be done full or empty. Another thing that can work is rubbing the spots with a trichlor tablet.

 

[Melt In The Sun]

Re: the brown stain, have you tried using ascorbic acid (vitamin C) to see if it lightens it? You can rub an unglazed vitamin C tablet on the stain to see if it has any effect. If it does it's an iron stain and the ascorbic acid treatment (procedure in Pool School) can be used to remove the stains. An acid wash should certainly get rid of it.

As for the black algae, an acid wash may or may not have any effect. It sounds like you're never quite getting rid of it, and your frequent "promiscuity" is giving the rash a chance to break out again. Have you considered some kind of automatic chlorine dispenser (liquidator, peristaltic pump, SWG)?