Backyard Aquaponics
A place to discuss aquaponics

Hellow all, im back again with more questions
but i know for sure that these questions and the answers can make knowledge more sharable and useful among the members and guest of this forum.

the questions are below:

1. is the numbers below are ok or not?
- PH is 6.8 to 7.4
- Temperature in the green house is between 25c to 28c
- Water temperature is Between 23 to 25c

2. My lettuce is taking more than 4 weeks to grow, its too slow, it took now more than one month and its still small, what can i do to make it grow in 4 weeks?
3. is the grow bed faster or the NFT "Which im currently using"?

attached is the current growth:

Temperatures seem reasonable though it might be a little warmer than lettuce likes.
pH seems ok.

The biggest thing you need to realize is that a new system takes time to mature.
Also, during certain times of the month, different things grow better. Look up a planting by the moon calender.

What do your other water tests say? How long ago did the system finish cycling? Have you added any potassium or iron supplement what about trace elements.

In general lettuce taking 3-4 weeks is actually really fast. Remember that many people who talk about harvesting the lettuce after 3 weeks are talking 3 weeks after putting seedlings into the system. Those seedlings might have been growing in seed starting trays for 2 or more weeks before that.

firstly TCLynx, i would like to thank you alot as uve been very helpful to me

The water test result is:
PH:6.8
KH:3D
GH:6D
NO2:1
NO3:10

what is the best result from the water test?
whats the best tempreture for the water to grow lettuce?
can anyone provide the moon calendar?
i thought that aquaponic did not need any extra nutrients such as potassium or iron supplement!
what do you mean by trace elements?

Trace elements can be locked out by certain pH values... generally 7.2-8.0....

So preferablly a system should be about 6.4-6.8... to avoid these issues... which is what the hydroponics industry does...

If you're suffering trace element lockout... then iron and potassium are the two most likely elements that you'll have to supplement...

For the water tests
You want to be sure your Ammonia and nitrite are both 0
you want the Nitrate to be somewhere in the readable range usually (though some people run successful systems without ever actually seeing the nitrate readings.)

If a system is not cycled up yet or the bio-filter not up to the fish load, then one may still see ammonia and nitrite readings and therefore needs to keep and eye on feed levels to avoid killing fish.

If high quality feed is given and the pH range of a balanced system is between 6.4 and 6.8 then perhaps supplementation is not needed but many people have found that with new systems, adding some seaweed extract (seasol or maxicrop) can benefit by adding some potassium as well as many trace elements. Iron is usually only needed if the source water is very deficient in Iron or if the pH is too high (I've had both problems in my system.)

I don't know what the best water temperature would be for lettuce, it probably depends some on the particular variety of lettuce as well. Lettuce is generally a cool weather crop and where I live, it's usually too hot for it by the end of April.