Plants not growing

[ronkirby2]

I am 4 weeks into fish less cycling and my plants are not growing very well and there is some yellowing.

Readings this AM were as follows:

Temp 80

PH 7.4

NH3 0.5 PPM

Nitrite 5 PPM

Nitrate 20 PPM

Is this normal and am I on track?

[TCLynx]

Looks relatively normal for this point in cycling.

Some seaweed extract and perhaps some chelated iron would help the plants.

[ronkirby2]

thanks for the info.  I am new to this and just wanted to be sure.  I added the Seaweed already do I need to add more?  How much of the chelated iron do I need to add?

[Vlad Jovanovic]

You'll cover your bases with most plants if you dose chelated Iron in the range of 2 to 3 mg/L (same as ppm). You need to figure it out between your total amount of system water, and the particular chelated Iron product you end up buying. (some are 6% Iron, some are 12% Iron, some are powdered, while some are liquid etc)...But whatever you use a 2 to 3 mg/L concentration in your system water should suffice.

If on the new growth, leaves are yelow, yet the veins are green, you need Iron.

If older leaves are yelllow, yet veins are green...that would be Magnesium deficiency.

If its general yellowness (leaves and veins)...that would in all likely-hood be nitrogen. (But since you have nitrates, that's probably not the case).

[Vlad Jovanovic]

I don't know if "sprinkling it over"...a media bed is what you'd want to do Dave. That seems to be about the absolute worst thing you could do. (But even then, probably not horribly, deathly bad).

Nor do I believe it can in any way "stress your plants" That is of coarse unless you "sprinkle it" on them...And probably not your fish either. You're not exactly gonna 'shock' them with ferrous Iron...That's just not how the physiology of Iron toxicity in fish works.

If you have any information to the contrary, I'd sure like to know about it...

Now if your raising your pH (with some sort of base) or lowering it (with acid) you should definitely do so slowly (0.2 pH points over 24 hours). But Iron chelates you can just dump however much you need (to achieve 2-3ppm in your particular system) into a 5 gallon bucket of water and then dump that water into your sump...or grow bed...

[TCLynx]

I usually add a spoon full of the powder stuff under the inlet of my grow beds when I add chelated iron.

[ronkirby2]

Thanks again for the great info.  Ordered the chelated iron today.  Could not find any locally in the Roswell, Ga area.  Will this help the plants to start to grow as well?  My wife planted a in the grown garden at the same time and the plants are twice as big.  I am learning so much but have really enjoyed this new found adventure...

TCLynx said:

I usually add a spoon full of the powder stuff under the inlet of my grow beds when I add chelated iron.

[TCLynx]

Chelated iron will probably help but it might not be the only thing that is needed.  Remember that a new system takes some time to gain maturity and supply everything needed for the plants.

[ronkirby2]

Today the nitrite is ph 7.4 , nh3 0 and nitrite 0 and the nitrate is 0.  I thought that the nitrate should up?  Is this normal at toward the end of cycling?  Is it safe to put fish in the tank now?

[ronkirby2]

Today the nitrite is ph 7.4 , nh3 0 and nitrite 0 and the nitrate is 0.  I thought that the nitrate should up?  Is this normal at toward the end of cycling?  Is it safe to put fish in the tank now?

TCLynx said:

Chelated iron will probably help but it might not be the only thing that is needed.  Remember that a new system takes some time to gain maturity and supply everything needed for the plants.

[Dave Roeser]

Sounds like you need more fish or bigger fish. Consider the amount of NO3 produced by the total mass of the fish, not just number of fins.

Temp is great for Tilapia. Remember as the temp increases the waters capacity for dissolved oxygen (DO) goes down and your fish will die.

pH OK for now

The plants are using up the nitrates faster than your fish are producing NO3 which in the first stage converts to nitrites and then nitrates which the plants consume. The conversion can occur in your biofilter or at the roots.

Consider how much you are feeding the fish too. They can't produce if you starve them, but don't over feed which is worse.

Dave

www.gardenfreshfarms.com

[TCLynx]

if you have plants in the system, they could be using up the nitrates.  Now that the ammonia and nitrite are 0 you can slowly start increasing the feed to the fish each day (as you monitor the ammonia and nitrites to make sure they don't come up again.)  If the ammonia or nitrite comes back up, back off the feed a little for a day or so till they drop again till you find the point at which you are either feeding as much as the fish will eat or feeding as much as you can before getting water quality problems (ammonia or nitrite being above 0.)

[Ross Williams]

I think its time to add some fish. Your nitrates are not going to increase until you get the fish producing some ammonia that bacteria will turn into nitrites and then nitrates for your plants to eat. Do you have large fish already elsewhere? If you are introducing fry it will take some time before they start producing much for the plants to eat. See Dave Roeser's post. Others have given you good info but you need the fish before you can call it Aquaponics. ;-)

 Good Luck

ronkirby2 said:

Today the nitrite is ph 7.4 , nh3 0 and nitrite 0 and the nitrate is 0.  I thought that the nitrate should up?  Is this normal at toward the end of cycling?  Is it safe to put fish in the tank now?