Backyard Aquaponics
A place to discuss aquaponics

Currently I am using Urea and my levels are a little high but ph is ok. I have added a little more water and think that the levels are to high because I have only a few plants in the grow beds. I have a 1000 litre fish tank and a 500 liter sump which cycles every 15 mins for 15 mins.
Thx guys and hope you all had a great new yr

If your system is new... and still cycling... then, while adding plants might lower/utilise any nitrates available... it wont affect the ammonia and nitrite levels...

They'll drop as the nitrification process fully kicks in... when you system is cycled...

Continuous adition of urea... will continue to push your ammonia levels though...

Perhaps ease off the urea for a week... retest in a day or two... and post your results up...

Which levels are high, how much urea have you been adding?

As Rupe said, Plants won't change the Ammonia or Nitrite readings. The plants use Nitrate.

I agree, stop adding urea until the ammonia level comes way down, then you need to wait till the nitrite starts comming down before you add much more urea. Once you can dose a regular small amount of urea and have the ammonia and nitrite remain at 0, then the system is cycled up to that load. You want both ammonia and nitrite to come to 0 before adding any fish.

Tricky part about urea is that it takes several days to convert to ammonia so it is way easy to overdose with that delayed reaction going on.

Tankyou for your help guys! I have taken some new readings and they are as follows
PH-7.6
ammonia-0
nitrate-0
nitrite1.0
I dont spose it matters about the PH as I have no fish and am using Urea. My water was also turning green and was told the sun was causing this so I quickly covered my tank.
So I spose I just add a little erea each fortnight to keep the levels stable.
Once again thx for your help

Just running some numbers:

if one has 1000liters of water then 1 gram of ammonia is 1ppm.
You get about 55% ammonia from urea.

So, if you have 1000 liters of water you can add about 2g of urea to raise ammonia levels by 1ppm, 3g would be slightly over 1ppm for 1500liters.

These numbers are rough, but should be close enough...


Many submerged plants (algae, etc) definitely absorb ammonia, but land plants don't seem to like it....

Yep, adding more urea is just going to increase the bacterial colony in the growbeds... not a bad thing... and raise your nitrate level... definitely not a bad thing for your plants...

But you want readings of zero ammonia and nitrites when you actually add fish... so don't add any more urea for a week before you get your fish..

P.S .... duckweed feeds on ammonia...