Greenhouse project

[dendronepthya]

I still don't think large tanks on top of one another would be possible without shading a very significant portion of the tank below. I am curious to know what you are talking about though. If you have a link I could take a look at, that would be cool.

I never came across anything like the tanks you describe when I was buying. I was basically looking for something that costs about $.50 per gallon. The rubbermaid tanks I picked up were recommended by many and were the best combination of rigidity and cost. Up to this point, I have not seen their equal in terms of durability.

The other possible issue with shallow tanks in a greenhouse setup like this is the lack of volume. Shallow raceways make a lot of sense when they are in a store setting, but in a greenhouse tanks with more volume are more stable from a temperature standpoint. With less volume, there are greater fluctuations, and that can be devestating.

 

[Julio]

I don't have a link but i will try and find out where they are sold and see if the company has a web site.

 

[Treeman]

dendronepthya,

The first thing you need to do is find a good agriculture test facility to test your water. It will be a test that would be for irrigation suitability or such. Depends on what they grow in your area. Just make sure that you ask them to test for Mg, Cu, Iron, Ca etc. You know, the things that you want in the water and things you don't. Also make sure they test for sulfur if the water smells. Once you know whats in the H20 it can be very easy to remove what you need to.

 

[wonrib00]

Here is a thought. I am not sure how your well pump works, but you may want to consider the idea of getting too much air in your well water. If you have too much air in your water, you will give your animals the equivilent of the BENDS.

 

[scubadude]

I need to find out what is in this water that is causing the high TDS.

Than,
Im wondering about the cinder blocks leeching out? I know big public aquariums and larger tanks (which yours qualifies) use them but im sure they would leech some yuckies. Do you notice any algaes growing on the cinder blocks themselves? Just thinking out loud

Rocky

 

[dendronepthya]

The first thing you need to do is find a good agriculture test facility to test your water.

I 100% agree. I talked with tech support at Spectrapure and they too agreed that a good water test needs to be done before any recommendations are made. I've contacted a local water lab that does environmental testing. Hopefully their rates are reasonable.

Im wondering about the cinder blocks leeching out?

The 900 TDS was straight out of the faucet.

It is very possible however that the blocks leached out even more calcium. I expected stuff to leach out. For weeks leading up to the mixing of the salt water, I had the blocks soaking in the water, and once a week, I would empty out all the water and refill the tanks. I know that those blocks can have some really funky things locked up in them.

 

[minfinger]

Get ahold of a Pool Sand filter from Walmart or soemthing like that. I think that would do it? Or maybe one of those Pool Supply places online.

So is that a no on the Sand filter idea. My local Aquarium uses them on everything.

 

[dendronepthya]

So is that a no on the Sand filter idea. My local Aquarium uses them on everything.

Not necessarily. A sediment prefilter may be necessary, which is very similar to a pool filter. The water coming out of the well is kind of murky with a brownish tinge. If I do go and get a commercial RO system, the presence of sediment and tannins will reduce the life of the membrane. A combination sediment/carbon filter may be necessary in addition to the water softener mentioned earlier.

 

[Treeman]

Iron and Tannin can be removed by pumping the water into an open top tank or pond. The iron will oxidize and settle out. Also the tannin will settle out and you can pump from the middle of the tank. Also a skimmer will take tannins out, but not much over 3-4 ppm I think it was.

Matt

 

[Julio]

Hey,
THe tubs i was talking about are on Dr. Mac and sons website on the home page.

 

[dendronepthya]

Julio,
Those are fiberglass tanks. They are probably the nicest thing you can buy for aquaculture. The problem of course is that they are about 5x the price of Rubbermaid stock tanks. If you want custom shapes, holes, or viewing windows, they are even more expensive. If I was starting a retail store where I would need a more visually appealing setup, the fiberglass tanks would have been higher on my list, but for a non-retail greenhouse, the cost was prohibitive. For a 1000-gallon fiberglass raceway, it was about $3000 + lots for shipping. That comes to a figure over $3.00 per gallon where the Rubbermaids are closer to $0.58 per gallon.

 

[Julio]

wow, i can see why you went with the rubbermaid, i never thought they were that expensive, i just thought that they were more effecient for coral farming.

 

[Ocean Image]

Dendro,

At IMAC this year I asked A. Calfo about water purification methods for a large greenhouse operation. Hands down he recommended a DI unit (not in conjunction with RO). Aparently they are less expensive to purchase, you can recharge the resins easily, and they don't waste water. I have yet to get back to him and find out what exact type of unit is needed. This may be an option you should look into.

 

[dendronepthya]

Ocean Image,
A huge DI chamber was actually my first option about a year ago. I was all set to have one built for cheap, and filled with tons of bulk resin from resindepot. Total cost would be around $2000 for everything (which is cheap, believe me). The two issues I had with this were:

1. I would have to recharge this system often. DI systems last longer the cleaner the water that is going in. The water at the greenhouse is the dirtiest I have ever even heard of. Most people deal with water in the 100-300 TDS range, and it is considered bad. 900 TDS is barely water.

2. Recharging... In theory, I love the idea. In fact, it still appeals to me. The issue that I have with the recharging process is dealing with some very nasty chemicals. Muratic acid or lye can really mess you up if an accident occurs. As cost effective as it is, you really have to factor in the risk of injury. Some may be more risk averse than others when it comes to this sort of thing.

 

[Ocean Image]

You are right, 900 TDS would have you re-charging the resin quite often. I wouldn't want to play chemist that much either.

Hmmm...tough spot.

 

[minfinger]

I don't know how much it rains in your area of OH, but what about buying 1 or 2 more 300G Rubbermaids and using the run off from the green house roof to fill the outside tanks. Once full and a water change was required, use a pump through a filter or something.

Of course, I don't know what you would do during the winter. Maybe shovelling snow into a heat tub?

 

[dendronepthya]

I almost forgot, even if the TDS was 900, you could still make DI work for you if only a small quantity of water was needed. I don't have that luxury. I will likely need between 1000-1500 gallons per month for top off and water changes. It is possible that I would be recharging the resin weekly on a commercial-sized DI unit.

So far, it looks like the pre-filtered (sediment+carbon+water softener) commercial RO system is the #1 option. It costs the most initially (roughly $4000), but long term, it is the least expensive to maintain. The membranes on the large commercial units are known to last for a few years before they need to be replaced, so the only thing to keep up with is the salt for the water softener and the carbon for the prefilter. The waste water on the large units is 1:1, so I won't have to waste an ocean of water every month. I'll probably be able to hook something up so the waste line goes to my parent's orchids.

 

[dendronepthya]

using the run off from the green house roof to fill the outside tanks. Once full and a water change was required, use a pump through a filter or something.

Interesting you mention that. The dad wanted to do something similar. Our gutters drain out into the corners of the greenhouse. It's not a problem really, but in the spring when it rains all the time, it does tend to accumulate in one part of the yard. He was looking at getting an underground storage tank to plumb the downspouts to and having a dedicated pump to send water into the greenhouse on demand. The benefit of this would be slightly cleaner water (in theory), and the elimination of the little bog in our yard.

So yeah, it's something that we looked into. Frankly, if he wants to invest his money into the system, I'd probably be able to find a use for it once it is installed

 

[minfinger]

Ha I knew I'd have a good idea eventually in this thread

 

[-Keith-]

Minfinger idea maybe worth considering, at least as a supplemental source. Rain water catchment systems provide pretty pure water. They can produce ~ 1 gallon of water / square foot area / 1 inch of rain.