AFreshwater plants

Question
QUESTION: Our plants are constantly dying. We have bought extra gravel to ensure the roots are covered, we use Tetra Plantamin plant fertiliser in the water and we add Tetra Optimat CO2 at night as that is the only test we do that comes out with a low result. The light was on 9 hours a day but we are now trying 10 to see if this is any better. We don't know what else to try.  Any ideas please?


ANSWER: I need more info.

What plants are you using, size tank, kind of lighting and the watts of it.

Also, there is no point in adding CO2 at night. Plants only photosynthisize during the day.

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QUESTION: On the instructions for the CO2 it says "the CO2 fertilisation should be released at night (ie without light) since plants can only absorb CO2 in connection with light.  It is recommended to ventilate during a period of darkness".  
We have a Juwel 58 litre tank which came with a Juwel Day-lite 15w bulb, recently replaced.  The plants are a mixture of the hardiest aquarium plants the shops supply ~ sorry I don't know the names. We've explained to the shop the problem and they have chosen what they think are the most likely to survive.  The KH and GH levels are always at the upper limits but nitrate is always <0.3 and PH is 8 or sometimes slightly lower.  
Hope this is what you need.
Many thanks.

ANSWER: I'd just like to say right now, that it is physically and scientifically impossible for your nitrate to be 0.3. Seriously. A billion dollar water purifier couldn't bring it that low. So either there is something wrong with your test kit or you are just reading it wrong, or maybe typing it in wrong. Anyways....

The very first thing I would do is get a stronger bulb. Some plants can survive in that but most can not. Get at least a 30W, but you may need to get more, I'm not sure what kinds of plants you have.

The whole point of CO2 is that it helps plants photosynthesize. Many hobbiest turn it off at night, however this can really mess up your pH so I don't recommend it. Just leave it on all the time.

Also, it is obvious that you are adding the CO2 improperly just by looking at your pH. CO2 lowers pH, and if it were being injected properly it would be around 7.0.

-Nick

---------- FOLLOW-UP ----------

QUESTION: Spelling error ~ should have been nitrIte, not nitrAte, but definitely <0.3mg/l. So there was no real need to be so sarcastic, I obviously don't know much about this as I wouldn't be asking and all you have achieved is ensure I won't ask again in future. Thanks for the bulb advice but I can't leave the CO2 on as it is a cylinder which I just press the valve to release a measured dose into a chamber which then slow-releases it into the tank, which I do AS PER INSTRUCTIONS.  In fact every thing we do is exactly what is advised in the manufacturers guide and as they are one of the top brands in the UK I am assuming it is correct so I will have to go back to them I guess.  Thanks for your time.

Answer
Here in Canada we use parts per million to measure nitrate, I did not know you were using mg/l. Sorry about that.

Anyway, like I said before you can get a stronger bulb. The bulb it came with is just meant for fish only tanks. When you upgrade to planted you need something better.

You haven't really given much to work with here though, I really need to know the kinds of plants you have....oh well.

-Nick