[txice]

Originally Posted by GpsFrontier

But try to call them yourself if you can.

Yeah, now that we are back from vacation and into "normal mode", and this is fresh on my mind again I plan to try and follow up on getting in touch with them somehow.

Originally Posted by GpsFrontier

This should be enough light to produce peppers, although a couple more hours might be better (but wouldn't cause the flowers to drop off).

The 12/12 light cycle is new. I've only had that going for a few days now. Prior to that I was on a 16 on/8 off cycle. The 16/8 cycle was in use when the blooms first began to appear and the flowers were still dropping off. Research seemed to indicate that flower/fruit development takes place during the dark period and most literature I've come across recommends a shorter light period during a flowering stage. The 16/8 cycle didn't seem to be working so I thought I'd give the 12/12 a go. On a side note when this system goes into it's "dark phase"...the room isn't totally dark. I have another system on the opposite wall in the same room that is still on a 16/8 cycle. It's a 6 T8 bulb fixture. Not super bright by any means, but enough to still give a small amount of light to the pepper plants. The T8 fixture comes on 2 hours before the MH and stays on for 2 hours after the MH goes off. Guess it sorta acts like a long dawn/dusk period...heh. But at any rate, the room itself isn't in total darkness for the full 12 hours for what little that tid bit might be worth.

Originally Posted by GpsFrontier

I am a little conflicted here. If the room temp rises to 72 and then the lights cause another rise of 6 degrees, that would be about 78 degrees and defiantly to high. On the other hand you said the roots are not becoming discolored. In my case the discoloring was due to extreme high nutrient temps (in the 90's). So I am not positive that you will see it at 78 degrees.

Your system is a combination aeroponic and water culture system, and as you said the lights cause the lids of the system to be warmer than room temp. Because the baskets and the main part of the root system hang above most of the solution, they might actually be adsorbing this heat and be warmer than the nutrients themselves. I am not saying that this is the problem but I would want to cool the nutrients down a bit to eliminate it as a problem. Especially because the flowers dying and falling off is typical of the root system being too warm.

I'll try to go into a bit more detail here and explain how we have the room setup. Initially when this was first set up we had nothing but a few standard hardware store bought T8 shoplight fixtures providing lighting for the plants when they were just getting started. These gave off little heat and the room itself was temperature controlled through the homes central air system and nothing else. When I built the systems the plants are in now is when I introduced the 400W fixture. It didn't take long to realize that the new light fixture, if left to it's own devices, heated the room a considerable amount. The room is kept closed off from the rest of the upstairs because we have cats that seem to like to eat the plants if they are accessible (I lost about half of my pepper seedlings this way when I first started because the systems were initially placed in an open area of the house ). It's not a huge room (under 200 sq. ft.) so it heated up fairly quickly. Plus, due to it being cold(er) outside we don't have the AC on, but rather the heat...so our central air was not cooling the room at all (and the light heated the room well beyond what our heat was set to). The high ambient temp in the room was causing the nutrient temp to raise. I think I posted about this in one of my other threads. We needed to figure out a way to try to reduce the nute temp because I knew it was getting too hot. First thought was to look into buying a water chiller. This wasn't really an option for us right now primarily because I have multiple systems that have independent reservoirs. A single chiller would not be able to cool them all. I'd either have to make significant changes to my systems or buy multiple chillers, both of which were not really options at the time. We figured the next best option to cool the water was to simply cool the room, so we bought a portable AC unit to place in the room. Bring the ambient temp in the room down....the nutrient temp would follow (to certain degree). We wanted to try and avoid having to do things like putting ice blocks or bags of ice cubes, etc into the tubs mainly to avoid all that extra amount of work. While we fully expect this "hobby" to be something we have to put time in to, we aren't in the position to be able to babysit the systems every hour or two throughout the day. So, at any rate, that's how we arrived at using the portable AC in the room...and it has certainly helped no doubt. Since employing the unit in the room the nutrient temp itself has dropped and stayed fairly consistent...staying within 1 to 2 degrees of the ambient room temp. Since the unit has been in place I've not recorded a nutrient temp above 73 degrees where as it was regularly breaching 80 after using the MH light but prior to having the AC unit.
Now...a note on my temperature readings. The nutrient temps are taken with my TDS meter. It can tell me both the ppm of the solution and the temp (in celsius). I have a calibration solution for the ppm part, but have never made any attempt to calibrate or check the accuracy of the temp reading of the pen. I can only guess it's reading relatively accurately....but I suppose it's entirely possible it's not. As to the room temps I have this unit hanging on the wall in the room: Acu-Rite at Lowe's: Deluxe Wireless Weather Station. It tells me time, date, inside temp and outside temp. The "outside temp" is actually what I'm using as the temp at the top of the lids. The system has a remote sensor. If you look back at the pics you should notice a little white box sitting on top of one of the lids. That is the remote sensor and what is displaying as the "outside temp". The actual temp at the top of the plants will be a little higher than what the sensor is reading simply because they are actually closer to the light than the sensor itself is. Not a dramatic difference I'm sure, but a degree or two wouldn't surprise me. I have no method currently to monitor the air temp inside the tub between the nutrient solution and the water. I'm sure it's probably warmer than the solution itself but would expect it to be cooler than what the sensor on top of the lid reads. Not a very precise system...but it's the best I have at the moment. Hope that gives you a better idea of how I'm setup and how I'm coming up with these numbers.

Originally Posted by GpsFrontier

If you need to replace some of the water daily to top it off, you might try dropping in block of ice instead. You could also try filling a Ziploc bag with water and freezing it, then doping one or two in the reservoir every day. I used to take one Ziploc bag and dunk it under water to fill it to keep the air bubbles out, then taking that one and placing it in another Ziploc and dunking and sealing that bag. Then doing it again for a total of 3 bags, to mimimise leaking and diluting the solution. Just remember not to fill them all the way to allow for the water expanding as it freezes. I also have a design for a simple ice driven recirculating cooling system if you are interested.

I don't need to top off the water at all really. These systems are pretty tight and evaporation is not a big issue. The only water loss I experience really is what the plants themselves use...and frankly that isn't all that much (yet anyways). From one nutrient change to the next I'm not really seeing a total water drop of more than about half an inch for the entire week. The tubs themselves are rated to hold 50 gallons. I actually put 12 gallons of water in them when I fill them up (enough solution to cover the pumps by about 3 inches of water).
Yeah I think we discussed the cooling system before. Something along the lines of running a line from the pump into a coil sitting inside a cooler filled with ice right? Like I mentioned above, I wanted to try and avoid having to deal with any situation where we have to repeatedly fill a cooler with ice or keep dropping in ice packs or what have you through out the day. I mean, if that's what it boils down to and I don't have any alternative I guess I'll have to make that sacrafice until I can come up with a better solution...but would like to avoid that if at all possible. If I did have to go down that road though, the idea we had was to simply use 2L coke bottles. Filling them about 3/4 full and freezing them and placing the bottle into the solution with the lid on to avoid any melted water from entering the nutrient solution.