Tomorrow’s Post, but Today

11:30 – I was making up nitrogen-free fertilizer stock solutions for biology kits yesterday when it struck me again as so odd that I’m using reagent-grade chemicals to make up fertilizer solutions.

Each of the solutions contains macro- and/or micro-nutrients. We have to supply them as three separate solutions because if you try combining them in the concentrations needed for stock solutions, you get a nasty precipitate.

So I made up 15 liters of Fertilizer A, enough for 120 kits at 125 mL/kit. Fertilizer A is basically just a concentrated solution of monopotassium dihydrogen phosphate and dipotassium monohydrogen phosphate. (You use a specific mix of the two chemicals to maintain the proper pH.) Fertilizer A supplies potassium and phosphorus, both of which are macro-nutrients (The “PK” in “NPK”). That solution, as expected, turned out clear and water-white.

I went on to make up 2 liters of Fertilizer C, which provides calcium, cobalt, and boron ions. Again, that solution turned out clear and water-white.

Ah, but then I went on to make up 4 liters of Fertilizer B, again enough for about 120 kits at 30 mL per bottle, and provides magnesium, iron, copper, manganese, molybdenum, and zinc ions. What a mess. There’s not a precipitate per se, but the solution is a cloudy brown. Cloudy enough that I don’t want to run it through my dispenser pump, which is a precision instrument. So I guess I’ll hand-fill 120 30 mL bottles. Better that than buy a new dispenser pump.

Tuesday, 30 June 2015

11:30 – Science kit sales are picking up, as expected. We shipped five kits yesterday, and have three more queued up to ship today, assuming that PayPal releases the hold on two of them. We’re at about 150% of last June’s sales. June is always a slow month, but better than the dead months of February through May. The busy period is the two month stretch from mid-July through mid-September, when we can expect to do 40% to 50% of the year’s sales. We’ll likely have many good days during that period when we ship more kits than we do some weeks during slow periods. I’m still making up solutions, filling bottles, and shipping kits, never-ending tasks this time of year.

Thinking about solar power the other day, it struck me that I already have good inverters, in the form of true sine-wave inverters built into on-line UPSs. I have three of those, totaling about 3500 VA, and 3.5 KW is more than enough to power the stuff I’d want to run with sine-wave power. All I’d really need is few high-output solar panels, a charge controller, and some additional gel or lead-acid deep-charge batteries. I’m not sure what voltage the on-line UPSs convert the 120VAC to for recharging the batteries, but I suspect I could just put the UPSs and battery bank in close proximity to the PV panels and run a heavy-duty extension cord downstairs that wouldn’t normally have anything connected to it. The UPSs wouldn’t be connected to AC power other than for the initial charge, and would therefore run all the time as though the power had failed. I’ll have to do some research, but it seems as though it should work and save me the price of a 3.5 KW true sine-wave inverter.

13:34 – I get really tired of reading really bad prepping advice on websites. I just read one on on water filters, where the author recommended the Platypus. That filter is one of the worst choices you could make. Here’s a detailed review that explains why. The reviewer actually knows what he’s talking about, in contrast to the author of the article, who doesn’t.