Fertilizer?

[meh]

I have a 40 gallon tank with 2 big rocks and three different types of freshwater plants.Do do you think I need fertilizer?.I will list my fish if you want me to.

[Crazygar]

What do you have for a substrate?

Gary

[ScottFish]

Also, what plants are you growing (how are they doing?), and what lights do you have? This will help us to help you decide if you need any fertilizers.

[Dutchman]

Actually . . . you should always use fertiliser, however little. But you must - at least in the beginning - test your water for nitrates and phosphates and find out how their levels move over time. That will give you an idea how much to dose on average. Unfortunately you cannot measure all nutrients in a simple manner (such as potassium, magnesium and sulphur), so you should learn how to judge the state of your plants to detect deficiencies. Stem plants are the best for this purpose.

Check-out this article: Plant Health Guide

[J.B.]

Probably the best question to ask is, do you want to mess with fertilizers?

[meh]

well to start with my plants growing fine and i have gravel over sand over gravel.my light is not a plant light

[Crazygar]

I would be a good idea to get some good plant lighting. 6500K to 10000K Bulbs are the best for this application.

Gary

[Dutchman]

For your info: (Ex: Wikipedia)

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To please your plants you should try to emulate sunlight. As Gary suggests, 6500K bulbs are probably the best, although - in my opinion - they’re a bit short in red , so it would help to add one 3000K bulb to your arsenal. Unfortunately, that wont give you the best of displays, which is why a lot of people mount one 10000K bulb above the front of the tank.
This is a useful file to consult: Fluorescent Light Spectra

BTW: Don't buy those expensive "champion" bulbs. The normal, cheaper "garden 'n kitchen" bulbs will do just fine. Instead, I strongly suggest to use electronic ballasts.

[lou zello]

i swear by a mix of FLORALSUN and ULTRASUN both are approx 6500-6700K and it is only my opinion gained from 50+yrs of doing the fishy thing,i allso think 10000K is too strong for a freshwater planted tank and it would only help grow algae,i think 10000K is more for saltwater but again only my opinion.as for fertilizer i agree on waiting to see how the plants grow BEFORE adding any.i have even stopped useing flourish and excel in my 55gal cause with approx 550 fish in it i don't think i need to add anything else!!!!!!

[Dutchman]

. . . i have even stopped useing flourish and excel in my 55gal cause with approx 550 fish in it i don't think i need to add anything else!!!!!!

Very sensible! The fish excretion and the decay of disregarded food is full of plant nutrients.
It may, however, be advisable to check nitrates an phosphates a few times a year, just to check movements.

[lou zello]

i do ALL the water tests at least once a week most times twice a week after my water changes and they never really change cept when i clean my two cannister filters then my nitrates will go up from 0 to just under 10 for a day or two,and i clean the filters every month or month and a half a week apart from each other.

[Dutchman]

Hmmm . . . Why are you testing so many times? Is there a special reason for this?
I've seen the pictures of your tanks. They look magnificant. Surely only stable tanks can look like that.

I test only once every 2 - 3 months for a few days in a row or whenever I suspect a possible deficiency problem.

BTW: I don't do water changes. I use so-called bog filters which are supposed to "renew" the water, so all I do is level-up with RO water.

[lou zello]

i do the test only because of the water here in conn,over the years the water co. has done different things to treat it and they NEVER let anyone know when they do something so it has become habit for me and i only use test strips for my testing which are cheap cause i get them in packs of 100.i guess it is really only for my own peace of mind!!!!! water changes are done because of all the fish i keep and don't like the the fish living in a toilet,and as in the WILD the water is ALLWAYS being replaced plus it is something i have ALLWAYS done

[Dutchman]

Thank you for that candid explanation. Makes a lot of sense.

There's nothing wrong with test strips. They're especially perfect for the purpose I suggested.

However, there are some fish that live in stagnant pools. The only refreshment they get comes from rain.