That ^^^^^ post was great!!! THank you Moe for the thoughtful encouragement! And as for my 'training tomato', that goes back to my OP, where I spoke about practicing on leafy green veggies.

You have also been most accomidating with myself and others and as you said, "...I don't care who you are."! You help ALL of us, reguardless of who we are or where we are in growing knowledge, ...hahaha, or lack of!!!! (I'm speaking for myself)
OK, let me answer your questions and maybe post where I'm planning on going with all this.
You nailed it! An original
SF2000, so no color control.
It was/is running on low and is now turned towards the tent wall, but still blowing upward from the floor. The clamp on it will only hold if suspended from from the hanging bar(s) in the top, blowing the warm air down and over the hot light towards the DWC. I'm here to learn! so correct me, but it seemed to me it was better to blow cool air up and out, rather than warm air down to recirculate???
The lung room for this little DWC is the spare bedroom/house. We have the the thermostat set to 74*, are running 2 humidifiers to keep humidity around 45%. Winter here in Pueblo is DRY!
LOL, at least daily. Right now it's more like every 2 hours. Like a new born baby.

I'll get some H202. Will the 3% work or do I need the strong stuff?
I have this on on it's way. Should be delivered tomorrow or Monday.
https://www.ebay.com/itm/165910371215 It claims to be a chiller and heater. We'll see when it gets here. THey're new, but are all over ebay and Amazon. Hope they work.
Good to know! It certainly has been drifting, but nothing radical. Went to bed at 5.7, woke up to 5.9. I tried to lower and over shot to 5.6 so added a triffle of silica to bring it back to 5.8. Since, it's drifted back down to 5.7 during the day, so I'll let it ride for tonight and see tomorrow morning.
I inoculated as you suggested in a previous post. I added the 5 ml in a 16oz cup of res water, soaked/dunked the roots (6" long) for about 2 minutes. planted the 'trainer' in the hydrocorals and poured the Orca solution into the res. Was that right??? Water temp has been kept between 70-74*.
Not sure I have all this straight in my head.
"pH up to 9, then down to 4", to kill bad bacteria?? OK, then back to 5.8, but is time or temp important for this bad single cell massacre?
Do I need to keep my 'extra' storage reservoir aerated?
nutes to feed my "killer res bacteria" inoculation?
It's in the garage right now, aerated and @ 60ish*, but I have a 300w submerable heater on it's way for Monday or Tue delivery.

Future plans will require at least 15gal in reserve for water changes in the 4x5gal system, so I have a 17gal tote 3/4 full with RO in the garage. Should I be giving that the pH sterilzation treatment and inoculate it ASAP???
Oh, and thanks for the 76* redline for pythium. I'm thinking along the lines of SLG with error on the cold side of temps. Especially in this sharp learning curve! A little slower growth, heck slower everything on a first grow should be helpful?
Any special brand of "bio-media" to transfer the good bacteria from one res to another?
with teachers and helpers like yourself, SLG, Steamroller, AquaMan and all the others that have contibuted, if I'm not enjoying myself, well, that would only leave MYSELF to blame. THIS IS FUN!!!! and you guys are GREAT!!!!!

Stay tuned, believe me, it's gonna get REAL fun shortly. My 2, 4x4 tents, one with the 5gal x4 system is just waiting for temps to get a tiny bit warmer. I expect to be popping 12 of Todd's (Authentic Genetics)
Original Haze (purple pheno) x NL#2 in about 10 days for a grow journal and will of course continue to ask for and use your experiance and advice!
and if you're still reading this, here is a funny story from my past about "dirt tossers" First off Moe, I resemble that remark

. Back in the mid 90's, I was honing my farming skills in Amsterdam. It's where I met Todd (Authenic Genetics) and we've been friends since, but back to 'dirt'. I had been into Possitronics several times buying grow supplies. Lights, ventilation, but the first time I went into Possitronics to buy dirt, hillarious! I'm at the counter and say, "I need to get about 15 bags of your dirt for my new garden". Cool as a cucumber, dude behind the counter grabs a broom and begins sweeping the floor, mumbling about how long it was going to take to sweep up 15 bags of dirt. What is he doing, I'm thinking??? Then with a rye grin he says "if you want some "earth" for you garden, we have it pre-bagged and ready to go, but if you want 'dirt', we're gonna be here a while!!! I busted up along with him! american terminoligy. In the Netherlands you garden in "earth" and you sweep up "dirt" from the floor. So if you insist: we're "earth tossers". Hahahaha!!!!