Tolerable ammonia PPM before flushing new system

[zach duenow]

Hi all...

My first post.  The brilliant fellas at 312 Aquaponics helped me set up an indoor home system.  200 gallon galvanized steel fish trough, and two 100 gallon galvanized steel hydroton plant beds.  Two 400 watt lights, one hps, one mhl.

Filled tank with tap, let flood and drain with heater and aeration for weeks before adding fish.

Just added 25 5" tilapia 4 days ago.  No plants yet.

Ammonia is spiked to around 4ppm...how long should I wait before I flush?  Any way to accelerate beneficial bacteria growth?

Thanks...looking forward to reciprocating.

Zach

[RupertofOZ]

If you can get some water, or filter squeezings from someone with an aquarium, or an aquarium shop when they do their filter changes... this will help "seed" your bacteria population....

 

With ammonia at 4ppm.... make sure you don't feed your fish... and I'd be tempted to do a 30% water change...

 

Not sure what your water temps are, or your pH... but the ammonia may well be toxic at that level.. even for Tilapia....

 

My greatest concern however is.... your "galvanised steel" tank and grow beds....

 

Are they only "galvanised"... or have they been "aquaplated".... lined with a plastic coating....

 

If not... ask for an immediate refund.... and buy something else... like Rubbermaid containers, Sylvia's stuff.... or use IBC's... like they do themselves...

 

Galvanised tanks will leach zinc... and kill your fish... no "ifs, thens, or buts"....

 

I hope they're not teaching people to use "galvaised tanks" in their training classes...

[RupertofOZ]

By the way... didn't they give you any instructions with the kit....

 

Like when to plant the plants, add fish... what to expect during the cycling process.... what do if xxx....

 

[zach duenow]

thanks for your helpful response Rupert.  312 didn't design the model, I did, they merely helped me pick pumps, tubing, and reconsider the layout for my given space allotments.  They truly were brilliant, and did have questions about the zinc.  I guess we'll see.  I have heard dogmatically positive responses on both sides of the zinc argument, I decided to just give it a try.

312 Aquaponics is kindly consulting with me on an ongoing basis...this is not their business. They are designers with systems of scale in mind (no pun intended).  They operate at a higher altitude than lil' ol me.

I have prepped some flushing water and will test tomorrow to see if ammonia is still getting worse, if so I will dump and fill.

Thanks.

zach

[RupertofOZ]

Thanks for that clarification Zach... and I'm gratified to hear 312 has given you good advice and guidance...312 are excused...

 

As to the "zinc argument".... well I don't know who might be suggesting it's safe... but they're just plain wrong....

 

There's plenty of academic studies that highlight the toxicity of zinc to fish... probably only second to copper...

 

And years of aquaponics experience, particularly over on BYAP (where people have been doing this stuff for over 6-7 years)... whereby every member that has utilised "galvanised" troughs/tanks... has ended up with dead fish due to zinc poisoning...

 

Seriously... do yourself a favour... and either junk them,... paint them with a "potable" rubber/bitumen... or get some liners...

[Jon Parr]

Zach, seriously, zinc has got to go. Not only does is kill fish, but fungi and plants as well. Zinc strips are sold to tack along the ridgeline on roofs, and just the runoff from rainwater will kill and prevent growth of moss. The good news is that zinc kills slowly, so you should be able to isolate and empty one tank at a time and seal it with a liner or coating, before everything goes belly up. Too bad you didn't add plants immediately and dose with ammonia the moment your system was operational. Would have saved you weeks of time, and weeks of pointless heating. Anyway, don't delay with fixing that zinc problem. If you've really heard on an argument in favor of zinc tanks, I'd sure like to see it. My guess is that someone tried zinc tanks and made a statement as to it's safety before zinc toxicity wiped them out. 

[zach duenow]

Uh oh...looks like I've got one heck of a project ahead of me.  Any ideas on liner or coating that won't be toxic.  My instinct tells me that any epoxy will be nasty.  Thoughts?  Many thanks for your concern and time.

[zach duenow]

also...here are two of the links that steered me towards the safety of galvanized steel.  But I yield to your expertise:

http://freshdirt.sunset.com/2011/02/are-galvanized-containers-safe-...

http://www.lenntech.com/periodic/water/zinc/zinc-and-water.htm

zach

[Jon Parr]

I took a look. Neither article references zinc to fish, and zinc runoff into a lake is not remotely similar to raising fish in a tank made of zinc. Zinc does kill plants, too, but perhaps not in soil in a zinc pot. Soil acts as a substantial buffer, and potted plants likely are not wet enough for long enough to contaminate the water. Nursuries sell a copper paint to use on plant containers, to "automatically prune" roots, so as not to become rootbound. When the roots touch the copper paint, they die, but the buffering ability of the soil keeps the main soil body safe enough for plant survival. Aquaponics is not the case, especially if you maintain your pH at 7 or below, where zinc does absolutely dissolve, and fish do absorb, eventually causing death, regardless of what that second article may say. Boats use what are called "sacrificial anodes", which are chunks of zinc placed on metal that makes contact with water. This is because zinc is so reactive in water, that other metals are saved by allowing the zinc to corrode first. Zinc equals fish death. I've no experience with paint liners, but there are discussions on this forum if you use the search feature.

[TCLynx]

And most of our tap water is of a high enough pH that simply running tap water though galvanized piping or putting water in a galvanized stock tank for the animals to drink from is safe enough.

But as noted, aquaponics is recirculating and the bacterial processes tend to acidify the water which will cause the zinc to leach into the water more as well as make the zinc more toxic to the fish.  And doing something like collecting rain water in a galvanized tank can leach enough zinc into the water to make the levels too high to be thought safe for drinking water let alone for fish.  Also, zinc in the water will tend to make any copper present, even more toxic to the fish.

Do a little search, there are several discussions going on about tank lining materials.  There is potable water safe Epoxi as well as some other bitumen or liquid rubber that may work or you could do pond liners.

[zach duenow]

Thanks guys...ok...I'm in.

Can't you see that I was merely in denial?...;-)...I just didn't want to admit that my brand new set up needs to be completely torn down and lined...ugh.  Well, this is what I got into this for...you find joy in the work and the learning, not just the end result.

Ok...next week I'll get 'er done.  Any good ideas on where to get potable liner?  I assume Home Depot poly isn't healthy.

Thanks all for forcing me out of my denial and saving my 24 beautiful Tilapia from an agonizing death...;-)

zach

[TCLynx]

Pond liner is what you want, not builders plastic.