Adding a grow bed to mature system.

[James Stratton]

System about six months old (six months since cycling and adding fish/plants) and, until now, Ive been running on a single 15 square foot grow bed for a 200 gallon tank. I'm adding a second grow bed of 12 square feet. Will this new grow bed cycle on its own? Is there something I must do? I'm a beginner and, unfortunately, did not give much thought to this when starting. Any info/suggestions/advice would be great. Oh, other info: PH 7.0-7.2, water temp 78 degree F, Nitrite 0, Nitrate less than .02 ppm, Plant leaves (older) yellowing. Have mineral rock dust on the way and still working (slowly) to stabilize PH.

[Pat James]

Cycling is to build up the nitrifying bacteria to numbers that will process the existing biological load (animal component).

You could add a growled and the plants would take up some of the available nitrates. At the same time, nitrifying bacteria will begin to establish themselves. After that, I would look at increasing the biological load since it appears that while your tank is cycled, you are not building up the nitrates. From the looks of the plants, they could use a little more nitrogen at the very least.

[Jonathan Kadish NYC AA Chair]

Nitrifying bacteria also live in the water column, so they will quickly find their way into the new grow bed. It looks like you might have a bit of an Iron deficiency.  If the rock dust doesn't do the trick...try adding some Chelated Iron( HEDTA) I use the Grow More brand.

[Harold Sukhbir]

Hi James,

This new GB(if you use a bell siphon) will require approx 30% of you FT volume water, plus your existing GB now at approx 35%, which leaves 35% or 70 gallons water in your FT with the 2 GB's filled at the same time. Rules of thumb allow 10-12 fish for that amount of water in your FT. If you use a maximum of 12 fish growing out to 1 lb you're fine, if you use more fish you'll need a bigger FT or incorporate a sump in the system. You can also design a constant flow GB which would have the system working as it is presently.

Sorry, seemed to misunderstand the question but I'll leave the comment anyway.

[James Stratton]

Thanks for the advice so far. I'm hoping that a little mineral rock dust will do the trick but I just have to wait and see. My fish tank is  a little over 200 gallons and my single growbed is using maybe ten percent of the water. I use pea gravel as a media and it does seem to be doing an outstanding job of keeping my water clean. The water is usually very clear-can easily see bottom of tank. So, there might be something to not having enough biological matter feeding the plants as well. I forgot to mention that I currently have twenty tilapia (barely fingerlings now) and about twenty little comet goldfish in the tank. When I was first cycling the tank, I had as many as eighty goldfish at one time. The ones in the tank now with the tilapia are the survivors of the cyclying process. It was difficult since I was cycling an outside system before winter was over. Had a couple of cold water emergencies through the process.

I certainly wish I would have designed the system with a sump tank but it was built around accessibility for my grandson. I have dreams of building a greenhouse next year and start a new (bigger) system for myself. My wife is just a little upset that I built this right next to the house.

[Harold Sukhbir]

Hi James,

So you're fine to add the new GB as i see. Mineral rock dust will certainly help with the deficiency or you can add some chelated iron if you wish. Wish your dream of the GH comes true for you, and me the same

[nimrod bash]

well nothing special , you do need to note PH levels , the new medium might change it so be ready to handle that

normally i integrate humus to a new grow beds to help kick start it , it's not a must just a time saver ...

do u have any periphyton activity in your fish tank ? if so dont b in a hurry to add more fish or nutrients

it means u got excess of nutrients and it's a good time to add a grow bed ...

am no plant expert but i think u got small fe deficiency ...