Backyard Aquaponics
A place to discuss aquaponics

This is going to be the 'practice system' before I spend a lot of money making screw-ups on the 600 gall CHIFT PIST. I had a go with the sketchup and lost patience, so forgive me, for now there are no visuals.
The basics of the system are:
30" X 30" X 30" EPDM lined FT. ( Roughly 100 gallons when filled to 26" deep)
72" X 20" X 16" EPDM lined GB (About 100 gallons and 13 cubic feet)

The pump is a laguna max flow 600 that will be plumbed with 1" cpvc to GB
Media is Red scoria (I have a bunch that I saved when I re-landscaped)
14 tilapia
Will use an Affnan bell valve to gravity drain back to FT
And also some sort of overflow

Here are my concerns/questions:
1. Does this sound like it would work?
2. It is REALLY hot here, it has been 115F and humid for the past week (I think that's about 46C), for about a month or two our highs average 110-115 and lows are about 90.
3. Not sure what air pump to get. Suggestions? I assume I'll need more air because of our high temps.
4. Again because of the temps, I wanted to go with CPVC (which tracking down was a massive and very trying hunt as well) as much as possible, but for the affnan, I will have to use pvc because as best I can tell those bell reducers are only made in dwv. See any issues here?
5. Will using a bell-reducer on the overflow pipe have the effect of sucking the water out more forcefully (like the affnan) without the siphon part? Was thinking a 3" to 1.5" reducer to 1.5" pipe. Do people drill small holes in these so if there's a problem there will still be a slow drain below the overflow height or just count on them to only keep the GB from overflowing?
6. If I end up not having enough media, I was thinking about adding a bag of hydroton, would probably add it to the top of the GB so it's easier on my fingers to mess around a bit in there. Any advantages to having it on the bottom?
7. How hard is it on the fish to cycle with them in there?

Thanks!

Hi Rachel,
Welcome to Aquaponics, as a newbie my self I will leave it up to the experts to answer your questions.

As for sketch-up there is a Quick reference card you can print that helps you to know what every thing does. You can find it here http://sketchup.google.com/support/?hl=en

Welcome and there is no turning back now!

Hi Rachel

Anwers as best as I can

1. Sounds like it will work

2. If it gets too hot, think about some shade cloth over the grow bed and tank. Works very well for keeping things a bit cooler.

3. Extra air is a good idea regardless of temperature, particularly if you can find a battery backup airpump. Good for keeping the fish alive if the power goes out.

4. Whatever piping you can find that works I guess. No real issue with DWC myself, I think some people have been concerned about lead (I think).

5. I have found reducers in standpipes slow the flow down if anything. I haven't found them necessary when using bell syphons. Having a slight rise in the drain pipe below the grow beds has worked better for me. Holes drilled at the bottom of the standpipe are OK if you are using bell syphons, the syphon will still work.

Some people put overflows as well as standpipes into their grow beds just in case the standpipe blocks up.

6. I would put the hydroton on top, as you say easier on the fingers

7. Not hard at all if you only have a few fish. A lot of people would advise against it but it can be done if you are carefull and test regularly. Have some water handy to do some water changes . If you are not confident of the outcome then fishless cycling is less worrisome.


Good luck with it, post some piccies when you get a chance

Thanks! It will definitely be under shade, swimming pools are around 90 right now. :/
I'm thinking I will make the grow bed 1/3 lava rock, 1/3 hydroton, and 1/3 non-granite small river rock (in sections, not layers) so I can test out different substrates.

I just got my tilapia today. I got 15 little 3/4" fry/fingerlings? off Craig's List. (We traded for a bunch of saved seeds so they were free!) She told me they are mixed sex and her original brood stock came from a commercial stock and that the males will be green with pink/red fins and the females will be striped and range from beige-ish to blue. Any ideas what variety this might be?

Still waiting for my pond liner and pump to show up, I'll start posting pics as soon as they get here.

For 100 gallons of fish tank you should get yourself an air pump that will provide at least .25 cubic feet per minute of air at 2 psi. Even through tilapia can survive really low DO levels compared to most fish, they will eat and grow better if you provide more aeration.

Many people do the gravel on bottom and clay balls on top for grow beds.

With only 100 gallons of fish tank, you may be pushing the limits on temperatures so definitely lots of shade and if you can encourage air flow across the surface of the water (I've heard of people setting up a fan to blow on the surface of the water to cool things in dry climates) it might also help.

I hope you like okra and sweet potatoes cause your summer heat is really going to limit your choices a bit from June through August at least. I thought it was bad here being up near 100 as the highs and down to 80 for the lows. I wonder if you could hook up a radiant chiller to run at night to bleed off some heat? But you may still be ok with the heat so long as you shade well and do a little extra to help cool things. I have my 300 gallon system out in full sun, there is a cover over the fish tank but the grow beds and towers are getting full sun with only a tiny bit of shade early morning and near sun set and the water temp in there has been staying below 95 as far as I can tell. I think it usually drops down to near 80 overnight. (kinda hard for me to say as I've had a terrible time finding reliable thermometers.)

I have some native adapted tomato varieties that do well in the heat with minimal water, eggplant, peppers, melons and squash too... but yes, it's hard to grow a lot of traditional crops here in the summer, but on the bright side, we can grow all winter long. (Which I guess you can in Florida too...)
Is a radiant chiller different than just a regular aquarium chiller? Maybe I could just throw a tray of ice cubes in the tank every night during July/August or rig up some sort of tray holding blue ice packs so the water coming through the siphon passes over it on it's way back into the tank... I don't know if the fish would like that or be shocked.
I thought some parts of Australia were pretty darn hot, any Aussies have similar climate??

I know some parts of OZ need to worry about overheating their fish during certain seasons.

If you are going to do ice packs (or even just juice bottles with water frozen in them) you would probably want to put them in for the day time.

A radiant chiller is just a funky way of saying run the solar pool heater at night instead of during the day so it will cool things (let the heat radiate out) instead of heating them. Like say if you have a coil of plastic tubing and lay it out where it will be under the open sky on a quick to cool surface and run system water through it at night, it can help cool the system more than just running normally would. Just make sure to shut that flow off before the sun hits it or you will cook the fish. In winter it might act as a solar heater if it can get enough sun.

In any case try to plan in some means of topping up the water since anything you do to cool the water is likely to cause more evaporation (aeration and splashing/spraying of the water helps cool things but it tends to do that by transferring energy through evaporation.)

I've had tilapia and catfish survive water up to 95 F before but do make sure you got lots of aeration and flow if the water is getting that warm and when the water is really really warm, you actually need to reduce the feed a bit (though with tiny fry this might not be an issue, biggest problem with them is keeping them from getting sucked through a pump and keeping them from eating their smaller siblings.

Why is it you feel you need to go with CPVC because of temps? The upper working temperature of regular PVC is 140 F If you are going over 140 F with your water, I doubt you will have any fish or plants left in your system to bother with.

The only situation you might deal with in AP where the water would get hot enough to be a problem is if you are actively heating the water (solar or boiler) and then it would only the the water to and from the heater that would be so warm.

I would guess that you really don't need to go to the extra expense and different glues/primers for CPVC since if you can't keep your water below 105 F, I don't think you will be running the system during the hot months.

Yes, I learned about the 140 PVC thing after I ran around to a million (well 5 or 6) plumbing stores. For some reason I was under the impression that PVC had a much lower temp limit and thought the CPVC would be more stable in general...which is probably also not true. However I already bought the CPVC, cpvc fittings and a glue that does ABS, PVC and CPVC, and don't feel like driving across town to return them. Once again I'm glad I'm doing the small test system because there's obviously a lot of learning going on over here.

This is all going on a massive stand on casters my old furniture-maker neighbor gave me when he moved. It's made of solid 1" thick cherry. It is 6 feet long and has a solid plank in the middle. I will add more reinforcement to the top part where the grow bed is going and also another set of casters in the middle of the unit. I'm estimating that the total weight of everything on it should be 1400 pounds or less (800 lbs of water, 100 lbs of tank/grow bed, and about 400-500 lbs of rock). I will also put bricks or blocks under it for added insurance. I know I couldn't move it while the tank is full, but I figure between summer and winter I could empty the water into a holding tank, move the unit into the sun/shade and refill....

You also got me thinking about the solar heating bit for winter. When I make the CHIFT PIST, could I just attach a length black pipe to the pump and do a few passes along the south wall of the greenhouse/shadehouse above the tank? As long as it doesn't increase the head height very much, does it matter if you add an extra 25 feet of length of pipe to the pump?

If you are going to add pipe length and not increase the drag too much the pipes should be as large diameter as possible which kind of defeats the idea as they would not heat up much.

Using fine black tubing is common to heat swimming pools and we used it to heat some lungfish ponds in my previous job. To do this a second pump would be good so it can be turned off at night, when it will become a heat sink, and to allow the primary pump to continue with its usual activities. The heating pump should push into a fairly large pipe which has lots of fine black tubes going up to another large pipe which returns the water to the tank. Its a very simple system and surprisingly effective if you have enough fine tubes and a suitable area to mount it.

Rachel! Welcome aboard!

PVC is great. I try to glue things, then leave them out in the sun to degass for a day. Once I can't smell anything in the tube, I figure it is safe. If I must glue a joint and run water without degassing, I only apply it to the outside of the pipe, not the inside of the fitting, on the hope that minimal glue will end up in contact with water.

FYI, I figure your growbed at 13.33CF, so the gravel will probably weigh more like 1300lbs. Always frustrating to crush things unexpectedly...

Insulation on exposed faces of containers helps reduce heat gain. Shade is important. Plants will help shade growbed. You could add pieces of styrofoam in exposed spots if desperate: a square foot of shade or foam would be equal to pounds of ice...

A fan on fish tank is very good, but only below certain temps. Test with an insulated pan (lid of a cooler?) of water, a fan, and thermometer to get an idea. I found mine cools to 72degF in hot weather (95degF).

BTW (TCLynx), scientific thermometers rock! I bought four of these a few years back and have been very pleased. -20 to 110C, 0 to 230F, accurate. Here is a pic I found on web:

On the solar heating/radiant chilling note. I've experimented with creating thermosiphon water heaters as well as using solar pool heater panels on my roof and even a passive drain heater on one set up.

The passive drain heater was actually very effective except it meant I had to remember to go open a valve as the sun started hitting the pipe and then also remember to close it again in the evening or I would wind up re-chilling things.

I've also found in my location that I have too much sun during summer and not enough during winter to really make the solar heating using the 2 pool panels I have very effective. I was using an old freezer chest as the hot water tank and I could get that up quite hot but I was not willing to run system water directly through the pool panels (unknown chemicals and plastics as well as the fact that bio-slime would clog the small tubing rather effectively and I'm not about to be going on the roof every other day to sort out clogs.) So I was doing a heat exchange system. It did have an effect but I would have needed a far larger hot water tank or materials that could have stood much higher temperatures for it to have had enough effect to keep tilapia alive for me over winter.

As for running a bit of black tubing, yes it can have an effect but If you are simply branching off the main system pump, you then need to remember to open/close the valves morning and night, and the slower your run water through the solar, the more it will heat. (think when you start running water from the garden hose, the water that has been sitting in the sun is hot but once that runs out, the water cools down to nearly well temperature. If running small tubing, bio-slime will tend to clog it and some black pipe (like irrigation pipe) might give off undesirable chemicals when heated so you will have to decide if you are concerned about that and if you want to go to the trouble of setting up a heat exchanger.

However, if trying to heat the water with just a bit of black tubing run in the greenhouse, I don't know that you will really get enough heating benefit to make it worth the trouble.

Thanks!
I just calculated that the gravel weight would only be 317 lbs if I used exclusively hydroton (40 lbs/1.76 CF), since I'm mixing it with the scoria it will probably weigh more, but that scoria is pretty lightweight too. Thanks for the reality check though, that probably nixes the idea about testing any river rock in this system!

72F water in 95F temps seems pretty darn good. I plan on using a small fountain for extra aeration in the summer, so that should also help with cooling. Especially in combo with the fan. Sounds like there's some more thinking involved before winter to keep everything warm enough.

I will be happy when the three trips a day to various plumbing stores and home depot are finished. I'm learning a lot of lessons, such as: If you don't bring your fittings with you, they will sell you the wrong size bulkhead and tell you it's the size you asked for, and call home depot before you drive over there to make sure their panel saw is working otherwise you have no way of getting the plywood home....

Hydroton is light, but will soak up some water and become about as heavy as water (otherwise it will just float). Even with the lightest medium, I would strongly suggest designing for at least the weight of water (1kg/liter=60(plus a bit)lbs per CF=800lb+. I made an error in engineering and ended up crawling in water and bracing my growbed-on-fishtank so it looks like a mine shaft.

Addictive fun, isn't it!

The longer low plywood construction in the picture, is that the grow bed? Plan on some extra bracing as my 8' long by 12" deep grow beds did bow out. Mine were built with 1/2" ply and 1 x 4 bracing on top and bottom and on the ends.

Also, I have been warning a lot of people about this since I've been replacing all my lumber and liner beds. Termites don't realize they have left the wood until it is too late, or maybe they do and were just after some water. If the system is going anywhere that a termite might have access to, then be very aware of this.

Also, below grade liner installs, I found tree roots invading the threads on the bulkhead fittings so I'm going to avoid plumbing through liners or tanks below grade if at all possible anymore.

I still have one grow bed that is lumber and liner, it is pressure treated lumber though. I am not building any more lumber/liner beds. I still think liner is OK but only if it is not touching wood.