I just ordered 2 jugs of Ferri-Tabs and plan to use them and report my findings here. (By the way, I am not affiliated in any way with Ferri-Tabs the 'guy' who sells them or the Slime Bag company. He has a deal at 2 jugs for $30 with free shipping for a limited time.)
After spending a few hours here over the weekend I've found a lot of interest here surrounding the iron issue so I thought I would contribute to the discussion.
I want to use them properly so that my report back to you is as accurate as it can be, so I thought I would create this discussion while waiting for them to arrive. I haven't been able to find detailed instructions anywhere, so I've listed my plan of attack below.
I've been on BBB since I opened my then 10 year old pool for the season in 2010. I love the BBB method, and my water is always crystal clear. The only issue I have is that nasty recurring brown staining. When I drop a vitamin C tablet on it, the area under the tablet clears immediately.
I've had staining issues for the last two seasons. In 2011, in order to lower my CYA, I drained and replaced about 40% of my water. That's when my trouble started.
I've used the AA treatment three times, twice last year and once in 2011. It works beautifully for me. Although my water is clean today, the stain is coming back. My guess is it's because I brought my water to shock level after taking the cover off last weekend (June 2nd). My PH is at 7.3 today and my target is 7.2. (I use the TF-100 kit, of course )
Here is what I plan to do (and in this order) when the Ferri-Tabs arrive. Please let me know if I should do anything differently. When they arrive, I'm going to go right at it.
1) Take my Chlorine down to zero.
2) Put the filter on recirculate.
3) Add AA.
4) After 24 hours put the filter back on filter (the iron should be completely off the liner by then)
5) Put the required amount of Ferri-Tabs in my strainer's filter sock.
6) Begin to re-balance the water.
7) Bring my FC back up slowly, and keep it on the low end as required for my pool.
It will be interesting to see if there is any color on my skimmer sock or in the site-glass when I backwash after using the Ferri-Tabs.
I'll make reports and post pictures here as I go.