My first system: Raft converted to Chop Charcoal Media Bed

[Paul Letby]

Hey Gang!  Thought I'd share my setup with you.  It's not pretty but it works.  I chose to enter aquaponics to keep my water change bill down as I was 'fish sitting' this winter.  My neighbor needed somewhere to keep his fish after he closed his pond so I agreed, seeing as I had a 30 gal tank with almost no residents.  I never saw more than 10 goldfish at a time so I figured I was good. Not so.  His water was so full of algae that I never saw all 60 at once!  That put me into emergency mode and I dragged my 55 gallon rainwater barrel into the basement and set up a filter with powerhead. 

After the two tanks cycled I realized that I'd have to do water changes very often to keep nitrates down.  Then I thought about aquaponics!  I'd seen the idea before, but never really considered it because an outdoor setup around these parts would only run for maybe 4 or 5 months out of the year before freeze up.  I did have a light stand in the basement with the barrel though.  So I chose the raft system simply because I had rafts on hand from messing around with hydroponics last year.  I grew lots of lettuce, but didn't like flushing old nutrient down the drain.  Now I don't have to worry!  I built the GB out of lumber with construction poly as a liner, ran some plumbing from the barrel to the GB, found an off season pond pump at the local home improvement box store (75% off!) and rigged it up to pump back into the FT.  Drilled lots of holes in foam to fit pudding containers I drilled more holes in and filled them with gravel, plopped them into the holes in the foam and plunked seedlings into them!  Confused yet?  I am.  Plugged in pump and watched!

Oh yeah, almost forgot.  To keep nitrates down in the 30 gal fish tank, I used some previous experience with aquatic plants to handle that.  4 weeks ago all my aquatic plants in there were just sprigs, except for the sword plant, but it's grown alot too.  I mixed up my own fert (micronutrients, P, K) so that the limiting nutrient would be nitrogen, and so far so good.  Only have hard scale algae at present, and that's very slow growing.  I'm not sure if I need the CO2 injection with so many fish.

Nitrate is almost unreadable for a few weeks now in both tanks.  It was quite scary high before the plants got going. 

Anyway, here's some pics for it all to make sense!

Here's an overview of basement system:

Lettuce view:

30 gal tank upstairs at feeding time!

[Paul Letby]

Noticing some chlorosis showing up on various plants.  Veins are green while the surrounding leaf tissue is yellowing.  This is showing up on newer growth more.  I'm thinking the high pH may be locking out iron.  I need to get a new test kit, and am just waiting til after Christmas just in case one makes it into my stocking!  The old one I had finally petered out.  So far my wide spectrum kit says I'm up around pH 8. 

I'm not adding any new media anymore so any traces of ash that made it into my system will be the last ones.  I can see where rinsing may have prevented this pH swing by washing away any ash. 

I don't like how high the pH is so I'm going to begin adding pH down from General Hydroponics, in very small doses spread a few days apart with tests in between.  Once I'm in the 7 range I'll stop and wait for the better kit.  If I don't get one I'll purchase the master test kit from Sylvia's store, and not just because it's the best price I've found.

[Sylvia Bernstein]

[Paul Letby]

Hope everyone had a great Christmas.  I did.  I also got a gift of a prepaid visa loaded with 100 bucks!  Now the problem will be not spending it all at Sylvia's store. (why shouldn't I? hrm...)

 

Anyway, I have noticed for a few days that the pipe extending down from my autosiphon was wet.  The wooden bottom of the GB was damp too.  This is not ok.  It means I have a leak in my GB.  Ack.  Well it could only come from the seal around that pipe, as I was very careful with the liner on installation.  So I drained the GB out, pulled out the guts of the A/S  and found that water had indeed worked around the silicone rubber seal I made.  My liner is construction poly, and I used aquarium silicone rubber for my seal between the fitting and the liner.  I'm thinking that because I didn't scuff up the poly that the silicone simply didn't stick well.  So I redid it after scuffing with sandpaper in a circular fashion around the hole, not leading into it.  Gotta wait 24 hrs for the stuff to set.

 

I probably should have asked whether I was using the right sealant before I went ahead and did it again.  So I will now.  :)  If it leaks again, what should I use?  Thanks.

[TCLynx]

hum, that's a tricky one.  Hay, why you get to use smillies but they won't work for me?

Anyway, What sort of fitting did you use?  Some sort of bulkhead fitting?

I don't know with the poly, I'm used to the epdm but I've usually not needed any sealant when I used uniseals or bulkhead fittings through liner and smooth wood.

[Paul Letby]

I used an improvised bulkhead fitting from the electrical parts bin.  I couldn't find a sealing ring to match though.  Maybe I should try to scout one out again in case of a new leak.  A properly fitted sealing ring would be the best answer I think.  At least it's not a major operation to do.  Didn't need to remove anything but the standpipe and fittings.  I propped up one end of the bed to keep any remaining water at the other end.

[Harold Sukhbir]

Hi Paul.

"I'm thinking that because I didn't scuff up the poly that the silicone simply didn't stick well."

Silicone is just a sealant and won't stick to poly liner. I usually apply a thin even film around the fitting and allow to dry, same as using a gasket or o-ring, then it can be tightened forming the seal. If you don't allow it to dry, it is squeezed out when compressed and also contracts, so not a good seal.  

Paul Letby said:

I used an improvised bulkhead fitting from the electrical parts bin.  I couldn't find a sealing ring to match though.  Maybe I should try to scout one out again in case of a new leak.  A properly fitted sealing ring would be the best answer I think.  At least it's not a major operation to do.  Didn't need to remove anything but the standpipe and fittings.  I propped up one end of the bed to keep any remaining water at the other end.

[TCLynx]

Oh, that could be a very useful point, interesting.


Harold Sukhbir said:

Hi Paul.

"I'm thinking that because I didn't scuff up the poly that the silicone simply didn't stick well."

Silicone is just a sealant and won't stick to poly liner. I usually apply a thin even film around the fitting and allow to dry, same as using a gasket or o-ring, then it can be tightened forming the seal. If you don't allow it to dry, it is squeezed out when compressed and also contracts, so not a good seal.  

[Paul Letby]

Great point!  That's exactly what happened this time too.  Silicone squirted out and as it dried it shrank and presto, instant leak.  I just drained the GB again and cut a gasket to fit.  I should have done that in the first place, don't know what I was thinking.  Your idea of applying silicone to the fitting and letting it dry is a great one!  Certainly alot easier than cutting out a little ring of gasket material.  If my gasket leaks I'm trying that idea.  That'd make a nice goey seal.

Harold Sukhbir said:

Silicone is just a sealant and won't stick to poly liner. I usually apply a thin even film around the fitting and allow to dry, same as using a gasket or o-ring, then it can be tightened forming the seal. If you don't allow it to dry, it is squeezed out when compressed and also contracts, so not a good seal.  

[Paul Letby]

Well, looks like the gasket is holding nicely.  No leaks.

 

I finally got around to detaching and rewiring my light fixture on the top tier over the charcoal GB.  Now I can raise and lower it as required to give the plants enough light.  I also purchased another T8 fixture that's actually meant to be used in a light stand.  Kinda flimsy compared to the other though.  I managed to knock a bulb loose while putting it all back together and have to replace a bulb that fell on the floor.  Oops.  At least it didn't fall and break into the GB.

 

Now I have enough light that salad greens and herbs shouldn't feel the need to stretch.  I can't wait to do this with some real money.  I grow tired of the 'el cheapo' solution.

[TCLynx]

At least by learning to do the el cheapo version, you probably learn a lot more.

[Paul Letby]

Now I'm tossing around the idea of building a growbed outside the house for the summer.  My fishtank barrel will stay in the basement 8' down from groundlevel to the floor though.  I'm trying to figure out a safe way to bring water up that far without buying a big expensive pump.  I think I may have to. 

I do have a window well about 30 gallons displacement on the south side of the house very close to the barrel.  I might pump water from the barrel up into a sump in the window well, then again pump water up from there into a gb.  The sump would overflow into the barrel.  If the pump died in the barrel the sump would run dry though.  Ack two pumps...  Any thoughts?

[TCLynx]

What is the height from the barrel to the top of the grow beds outside?

There are pumps that can handle moving some water at an 8-10 foot lift without breaking the bank.  I'm currently using a 145 watt pump to lift water about 8 feet for my new 300 gallon fish tank tower system and I expect moving outside for summer will save you more than that by allowing you to turn off the lighting indoors.  You also probably don't need to move that much water so could probably run a smaller pump so long as it can handle the head.  There is a high head Quiet One pump model that I think uses between 110-120 watts.