Regarding getting my rez temp up... I have a plan. Access to the reservoir is very limited (a design concession to grow chamber height). So I can't drop in a gallon jug. But I can heat the water before making a new batch of solution. Currently, the rez is about half full (5 gals). I'm not really ready to add more nutrients, or to flush just yet. So, tomorrow, I'll pump about 3 gallons of solution from the reservoir and into my mixing bucket. I will then add the appropriate amount of boiling water, mix it, and pump the new warm solution back into the rez. I'm thinking I want to bring the 5 gallons of solution in the rez up to 75 degrees F. In a day or so, the temp will should be back down in the mid-to-low 60s. So I'll repeat this as needed until I can install the heater. But first I need to determine how much hot water to add. I’ll do this by experimenting in the kitchen with smaller quantities or by leaning on the calculations stemming from the Law of Conservation of Energy available on the internet or an old text book. Hmmm… Better warm up the old calculator. Better living through chemistry, right? Other comments will be addressed in the next post. And hopefully I'll have an answer to the water ratio problem to share as well.
Be careful with boiling water. You do not want to get that sprayed on your roots! I think 75 is too hot. Just a few cups of warm water here and there to bring it up to nice 68. The biggest thing is going to be consistency and preventing dramatic changes to the temp.
So… How much boiling water will it take to increase the temperature of 5 gallons of water from 60 degrees to 75 degrees? And the answer is... If there is no heat loss, adding .55 gallons of boiling water to 5 gallons of 60 degree water will bring the total temperature up to 75 degrees. The details: First convert to Celsius. 60 F = 15.6 C and 75 F = 23.9 C and water boils at 100 C. Disregard the fact that water at 100 C weighs less than nutrient solution at 23.9 C. This allows us to use gallons as a measure of Mass, which it isn't, but since we're growing weed and not making rocket fuel, it's just fine. Law of Conservation of Energy basically says that the total amount of energy lost, will equal the amount of energy gained. In Mathematical terms the law can be expressed as: Qgain=Qlost Or… m (C) dT cold water = - m C dT hot water Then when we put some numbers to it… 5 gals cold solution (23.9 C – 15.6 C) = -Gals Hot Water (23.9 C – 100 C) Simplified… 41.5 = Gals Hot Water (76.1) Or… Gals Hot Water = 41.5/76.1 And… Gals Hot Water = .55 Gallons or 70.4 oz. or 2 pints and 6.4 oz. or 2082 ml or 2.1 litters Isn't Science just great!!!
OK OK. I'll do it all over again. How about 70 F. Remember, I'm mixing this in a bucket, not in the reservoir. By the time it gets to the roots, the solution will be at 70 or 75 degrees.
Moving 5 gals of 60 degree water to 70 degrees will require .47 gallons (just under two pints) of boiling water. Of course this is all theoretical. What actually happens may be totally different.
Couple other things... The Hanna should measure pH, ppm, and temp, but there must be a short in the unit, because when I dip the temp probe in the solution, the ppm and pH go haywire. Good news is that weather forecast is for nice warm weather for the foreseeable future. Budz, not sure what strains are next, in one sense, since it's been so cool, I'd like to try a blue or purple strain. But odor is an issue, and as 1776 has been saying, there are some good low/no odor strains out there. In the end though, it will probably be what strains look good locally.
Here are a few that I checked out. However, there are a dozen or so more strains out there that offer low/no odor. I'm sure you'll find something you like. White Ice (read mixed reviews) LOW odor Blue Mystic (midi) NO odor Chronic (kind) LOW Oasis (kind) LOW BC Mango (kind) LOW Grapefruit (kind) LOW Cinderella 99 (kind) NO I just started five California hash plants. They have a semi low amount of odor. However, your only fighting the odor for a couple of weeks since they finish bloom in under 40 days.
1776, Thanks for the list! I guess it's time to start thinking about the next grow. It's also time to take a critical look at my cabinet and aero system. All and all, I'm happy. But there are a few things that need to be redesigned. Sick0, glad to have ya stop by.
D71/B39: 1-4-12 @ 5:50 AM Garage Temp: 68 Grow Chamber Temp: 79.5 Grow Chamber RH: 38% Reservoir Temp: 62 Reservoir pH: 6.1 Reservoir ppm: 1070 Reservoir volume: 4.7 I suspect that the low reservoir temp may be causing the slowdown in growth. So, I’m adding boiling water to increase the temp. Based on yesterday’s temp of 60 F, adding about .55 gals of boiling water will bring the 5 gallons in the rez up to 75 (law of conservation of energy). Added: .5 gallon boiling Ralphs RO Water 0 ml Grow 3 ml Micro 4 ml Bloom 1 ml MagiCal 1 ml Hydroplex 6 ml pH UP This brought the reservoir temperature up to 75 degrees F (although it might have gone a couple of degrees hotter with more mixing) Added .5 gallons of 63 degree water. After all additions: pH: 5.5 ppm: 970 Reservoir Temp: 73 (this is higher than expected) Adding .5 gallons of boiling water to 4.7 gallons of 62 F yielded the expected result. Although with the warm weather this week, it was too much. I will check the reservoir temp again tonight and adjust accordingly. I though adding .5 gals of cold water would bring it back down to 70, but in hindsight, the calculations don't bear this out. And neither did experience. Oh well. I’m shooting for 68 F. Hopefully the rez temp will drop significantly over the next 12-24 hour. Unfortunately, the forecast calls for a high of 76 here today. Fortunately (this time) I don’t expect the garage temp to go much above 70.
Perfect! Just when I need some cool weather to chill my rez, a heat wave hits. High 80s all over LA today!!!
Brief update... At 8:30 PM last night (14 hrs after adding the boiling water), the reservoir temperature was 63F and the pH was 5.8. Garage temp was 70. Moved the fan up about 4â€. Did a light spray of Serenade. D72/B40: 1-5-12 @ 6:15 AM Garage Temp: 70 Grow Chamber Temp: 82 Grow Chamber RH: 39% Reservoir Temp: 62.8 Reservoir pH: 5.9 Reservoir ppm: 1010 Reservoir volume: 5.5 I was worried that the rez temp would be too high. But by last night, temp was already back down to 63. Having a difficult time keeping the pH down. Moved up .4 in the last 24 hours.
Just found this journal, great read. I like your planning. What CAD software are you using to create your diagrams? They're fantastic. I grow in a cabinet too, with a good scrog you can get a few zips for sure. A zip (or a zone) or basically any unit that begins with a z is an ounce because of the short hand "oz" Keep up the good work!
hey Chiro, Thanks for stopping by. I use Photoshop to make my drawings. I have Autocad 2011, but am not good enough on it to work efficiently yet. Maybe by the end of the year. It's a really difficult program. Nothing at all like Photoshop, which while not basic by any means, is at least is usable without months of instruction. I got it. Oz=zip=zone. And lb=elbow. I'm a bit out of touch on the banter. Hey, just read your journal. Man! you had to be stoked with your first grow. And #2 is looking pretty dense as well.
D75/B43: 1-8-12 @ 7:00 AM Garage Temp: 65 Grow Chamber Temp: 79.5 Grow Chamber RH: 37% Reservoir Temp: 60 Reservoir pH: 5.8 Reservoir ppm: 1130 Reservoir volume: 5.0 The aquarium heater does not seem to be working propery or at least as I expected. It was set on 68 and when I pulled it out, the green light was lit and it was not hot, even though I confirmed with two thermometers that the solution temp is 60 F. I reset it to 72 degrees and the red light came on. We'll see if this helps. Upped the concentration of Serenade to 30 ml per pint of water. Did a full spraying. And some photos from yesterday:
Looking good, man! Do you plan to flush anytime soon? I'm noticing that your tips are looking more burned than from the pictures 5 days ago. Are both plants equally burned? If you can get your heater to stabilize the temps in the res, it would probably be a good time to flush and start with new water/nutes. It's kind of odd on the heater being so far from the real temp. Usually they only vary by a degree or two. You probably want to keep a close eye on it. Don't want an accidental 100 degree res!
That train wreck is getting frostier and oh so freakin amazing. With all your low temps I wanna see some GDP in your next grow haha. Youd have such amazing colors. THink about ittt.....