Pro Mix Peat Based Medium PH Adjustment

Stats:
Nirvana Bubblicious
Four, 125 Watt CFL's with home made horizontal reflectors
Pro-Mix BX medium
3 Gallon container
Flowering stage aprox 3 weeks Lights 12 on, 12 off
Nutrients, Miracle Gro Bloom Booster 10-52-10, One feeding at 800 ppm & PH 7.1.
Watering every 2-3 days at 2 gallons, bottled RO purified water with minerals added PH 7.1
2 straight H2o waterings since bloom ferts added.

Previous problems/symptoms: Early N burn evident but recovered. Initial medium already had ferts. Low PH from peat based medium some PH spotting and mottling. Have increased watering and nutrient soloutions to 7.1 PH.

I have one bean flowering for aprox 3 weeks now in Pro Mix BX. 12 on 12 off. The PH was at 6.1 last week. I began watering with RO, purified H2o with minerals adjusted to 7.0-7.2 with PH up. The PH is now 6.5 with the 2:1 media/distilled H2o saturation test. Hanna 3 way meter at .5 conv.

Question is this, is the PH up watering adjusted water enough to sustain the PH or do I need to add dolomitic lime in soloution?

Next time I will incorporate the lime into the medium prior to planting.

Thanks

It looks to me like you are well under control. The plant looks healthy.
I would keep doing the adjustments the way you have been so far- I'm not sure how well you will be able to get lime, even in water, to go into the soil evenly. Lime only dissolves to a certain extent in water, and you will actually end up with a suspension rather than a true solution... you could end up with pockets of different pH in the medium, and if you have ever seen symptoms of pH problems in poorly mixed dirt... well, you don't want to!!! hahaha I've done it back when I used peat moss, and you'll get like one branch acting one way, and the next totally different, and it's just nutty.
Hm wht else... promix BX is already limed at the factory if you can get that stuff.
Personally I avoid peat-containing mixes like the damned PLAGUE. Not just the low pH, but they hold a lot more water than I really like.
A mix of compost and LOTS of perlite is nice; if you have an Agway dealer near you they sell composted cow manure with humus $2.50 for 40 lbs, that's what I use mixed 2:1 with perlite, and it is naturally buffered RIGHT AT 6.8-6.9!!!
Anyway just something to think about.