Smart Blue Polytunnel Polythene

Good question. Unfortunately, I don't have a good answer. You should PM Sanjay, as he's the resident lighting expert.

There are no light filters in the reef hobby, so I assume they don't work. I think they change the appearance of light by filtering out higher (690 nm) red wave lengths, but fail to increase (420 nm) blue wave length. I'll admit this isn't a qualified answer however.

You would have to use a UV filtering second layer, as the product you mention has no UV filtering capacity.
 
<a href=showthread.php?s=&postid=10173149#post10173149 target=_blank>Originally posted</a> by Philip Root
I use a product like this, I like it.
Click to expand...

Do you have any updated greenhouse pictures you could post. I'm impressed with what I've seen so far of your operation.

I would like to use a product like this, but I need some assurance before I commit. Does it render a higher colour temperature to compensate for the shallow water of GH mariculture tanks? Do you have a link to the poly you use?
 
ChromatiNet Blue

http://www.signaturesupplyonline.com/

Well the reason I used it is becasue it filters out red and yellow light. After seeing an experment that was done with colored leds I know I want litttle to no red light and lots of blue. The blue cloth takes in ever color but blue. Several people that have fish greenhouses told me to stay away from black so I did.

Pictures, I am working on new pictures. I am having to change website host so once that is done I will up load more pictures.
 
<a href=showthread.php?s=&postid=10177201#post10177201 target=_blank>Originally posted</a> by Philip Root
ChromatiNet Blue

http://www.signaturesupplyonline.com/

Well the reason I used it is becasue it filters out red and yellow light. After seeing an experment that was done with colored leds I know I want litttle to no red light and lots of blue. The blue cloth takes in ever color but blue. Several people that have fish greenhouses told me to stay away from black so I did.

Pictures, I am working on new pictures. I am having to change website host so once that is done I will up load more pictures.
Click to expand...

That's very assuring. The site you linked has more credibility than the UK site, and from what I've seen on your website, your opinion is qualified.

My biggest concern going into this GH venture is colour temperature, and overheating. Mariculture greenhouses seem to produce brown corals as a result. Both of these issues are addressed by the blue poly, so it should be a night and day difference.

I haven't seen any experiments with LED lighting, but the fact that corals have evolved for millions of years in (refracted) blue light, is enough for me. After the sun travels 94 million miles to reach a greenhouse, you definitely need more than 12" of saltwater "lens" to replicate natural lighting conditions.

Good luck from the colonies englishreefer. You will have greater cloud cover than we get, so light inhibiting and cooling factors aren't as important for your location.
 
I would be using two layers of polythene with air between. I would use a UV blocking layer on the outside then the blue under. I imagine that in summer it is gonna be perfect for helping temps and shading yet still allowing most light blue through.

My concerns are in the winter. I do appreciate that even at my latitude that their is still ample light for propagation. However i fear that this polythene may shade the GH too much meaning i will require supplement lighting.

Philip do you have any PAR readings in your GH. what is the difference between inside and outside PAR.
 
Yes I have par readings, the difference on 30% blue is about 40%, 50% blue is about 50% and 70% is about 75%

But the way that you talk about the poly is wrong, The Blue is on the out side. If you don't do that it traps the heat inside. The Blue is not an air layer. That is good because I have 3 blues of different shade for different seasons.

I am thinking that you want no uv filtering. But no hard facts. I am using no uv filtering, and I think I would like a bit more.

Also new pictuers are up on the web.
 
I didnt really think about trapping heat between poly layers. I was thinking that as the blue sheet would be doing more filtering that it would break down faster. Iguess they would both be changed at same time so is prob not much of a concern.

I am still trying to get my head figured around heating. I am aware that even on cool sunny days the temp in GH can still be very high. To what exstent is this true, I mean is their a basic sort of figure, ie with direct sun with slight wind the GH is 20 degrees higher than outside. In the summer here temps rarely get above 80 outside. What sort of temps can i expect inside.

thanks for you input, this is most helpful
 
The blue sheet dose not trap air, I was not sure you understood that. You have two layers of poly and then the "Blue Poly" wich is more like a net.

Heat is not a problem with the swamp cooler. I have seen days with the outside temp of 102F and only get the greenhouse to 84- 86F If it shuts down for even 5 mins the temp will go up fast.

Cooling the greenhouse has not been much of a problem, Heating in the winter is a whole different problem.
 
I see what you mean now, I was meaning, using the blue to actualy cover the greenhouse. Thinking about it now i guess this is a very bad idea, seemed good at the time.

I am hoping that being in a cooler climate that i will not require a swamp cooler. My plan is to use only an exhaust fan and fans over the vats for cooling. As the construction will be over winter i will have time to install more measures over spring if it proves to not be enough.

I am sorry to be a pain, your help is greatly appreciated.

Off topic, i am completly baffled to figuring out what size air blower im gonna require. What sort of size would you think id require for eight 5x5x2 vats. All softies for time being so flow will not need to be to heavy. If i turn any sps i will probably add some carlson surges on top.
 
As far as blowers go. I would buy one larger than what you require as they are fairly efficient, and you don't have to replace it if you add more vats or change your number of air lifts.

I would go with a 1/2 HP unit, but you will only need 1/4 HP for what you are planning. I had a 1 HP blower that ran 2000 air lines, and may have done much more. I used the same blower for 200 air lines when I downsized later on (freshwater). It provides an even flow, so it doesn't matter how much air you actually use. The 1 HP blower used about 10 amps. You could use it to fill your poly as well, as it is the same style. Gast and Sweetwater are the two big manufacturers in North America. They will be able to tell you how many lines it can run. http://www.gastmfg.com/technical.html

It's been a while, but if I remember correctly, it would only push about 30" deep. I think some of these people with deep vats use a piston pump. You will be fine at your 2' depth.

As far as cooling goes, you should be fine with a ridge vent. They're cheaper and easier to operate than an evaporative cooler (swamper). You definitely need a swamper in the souther US though.

For heating, you should use 1" styrofoam sheets over each vat at night. It's labour intensive, but it pays off. It will also help with humidity and limiting evaporation top-off.
 
Styrofoam sheet over the tanks would help a lot but that is a lot of work 7 days a week, NO winter vacations.

I use a german made simmions, when looking at blowers the sweetwaters drank power. I payed almost twice as much for the blower but it will pay for its self fast. My water and power bill together is about 250 per month.

Air lifts in the winter, I do not use the lifts in the winter because they cool the water too much.
 
I year you about the styrofoam top. We used them for a year on 4'x8' vats in a retail store, but it was a lot more work than it sounds like. They also introduce the risk of dislodging air lines etc, as you pull them on and off. Then of course you have to store them.

If you have the money, you can buy an automated system that rolls out a foil "blanket" to trap the heat in the greenhouse. This can be done manually, but it would be almost as much work as the styrofoam lids, with less efficiency.

You can use the RC calculator to find out how much energy the blower will use. Remember, they have a lower operating draw than the start-up amperage.

http://www.reefcentral.com/calc/tank_elec_calc.php

I've haven't looked into them yet, but there are some windmill air pumps on the market. They're a lot cheaper and easier to use than an electrical windmill, as there is no need for expensive cables and battery systems; however, I don't know how much air they produce, or if the air can be compressed for uniform pressure. Of course you need wind 24/7. They use them mostly for farm pond applications.
 
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