help me with fert doseing - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 10 Old 04-19-2013, 02:50 PM Thread Starter
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help me with fert doseing

ok just to get this out in the open firstly - im not wanting to use dry ferts and am confortable with flourish for the time being.

so my tank has cleared up and stayed clear for the past two w/c's all while using a single dose of flourish comp x1 a week. well since the most recent w/c ive put in a second dose - 3 days after w/c and first dose.

how do i know if my plants want more? will they show deviancy's or just not grow as fast?
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post #2 of 10 Old 04-19-2013, 08:41 PM
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First you need to establish what parameters you want to start out with. Take a look at the macros in Flourish Comprehensive. I do not see how you can keep plants healthy with such low amount of macros. Some one else may have to step in and explain. There is a very good online calculator that will give you the results of your dose. Then you decide to either increase or decrease your dose. Go to:
Yet Another Nutrient Calculator
it would be great if someone can post what are good ranges for the parameters.
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post #3 of 10 Old 04-19-2013, 10:28 PM
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I think the way flourish comprehensive works is to provide sufficient micros and assumes that the livestock in the tank can provide the macros...
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post #4 of 10 Old 04-19-2013, 11:17 PM
+1 =p

Likely gonna have macro problems using only flourish.

These levels are for high tech, I know you have the light just not the CO2 but its still doable IMO.
Nitrate 10-30 ppm
Phosphate 1-2 ppm
Potassium 20ppm
CO2 15-30ppm

.... I'm probably drunk.

This is how I lurk

Last edited by Mikaila31; 04-19-2013 at 11:27 PM.
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post #5 of 10 Old 04-19-2013, 11:21 PM
I think so too, although I dose Flourish Comp and my plants are having some problems. I may just need to rethink the way I am dosing it - maybe not enough. I only have 7 Pristella Tetras too and I feed them a little once a day - they finish the food in about 30 seconds.

I just tried the calculator linked above for 1 ml Flourish Comp (premixed category) and results of this dose, and I like the calculator a lot. I think I'm dosing 5 ml / 6 for 10 gallons. I think that's 20 eyedropper drops per ml. I'll incorporate this into the way I dose, maybe dose the same thing twice a week.

Last edited by equatics; 04-19-2013 at 11:38 PM.
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post #6 of 10 Old 04-20-2013, 07:11 AM
Oh - someone told me to dose for the actual amount of water in the tank. That's minus the substrate, hardscape, and anything else that takes up space in the tank.
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post #7 of 10 Old 04-20-2013, 11:48 AM
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That advise came from me I believe. it is more accurate way to dose your tank. I have a 75 rated tank but after the actual interior measurements and the displacement of water from gravel, it comes out as 58 gallons. Big difference! But then I add 4 gallons back on to that number because not all the water is displaced by the Flourite gravel. So actually its a guess on how much. In any event, I am closer to the actual capacity then 75 gallons.
If one has a sand substrate, then not much water is between the grains.

Last edited by rjordan390; 04-20-2013 at 11:51 AM.
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post #8 of 10 Old 04-20-2013, 12:30 PM Thread Starter
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where the tank is now, if I do two caps in a single day I get green water, if I wait 3 days between single doses the tank stays clear. while I am constantly adding plants the fert will be used more quickly right?

just kinda looking for a way to tell when to bump the ferts up with constant additions of plants.
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post #9 of 10 Old 04-20-2013, 01:26 PM
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The issue is always balance, which is what most posts are dealing with in various ways. You can have a thriving, lush 90g planted tank dosing 1 teaspoon of Flourish a week. Or you can have a thriving, lush planted 90g tank dosing dry ferts every day. But doing the second method in a tank balanced for the first method will be disaster.

First thing one has to decide is what you want in the end, as a planted tank. Then you work out the balance to achieve that end, which includes the light intensity [duration can always be adjusted, but if the intensity is not sufficient for what you want, or is too high for what you want, trouble will follow], fish stocking, fish feedings, and nutrient supplementation. The nutrient supplementation includes all nutrients you intend to add artificially, meaning, not relying on what is there naturally. And the latter depends upon the fish and feeding, plus your maintenance.

Tom Barr once told me that you first select your light--keeping in mind that you need the light suitable for the type of planted tank--then you add nutrients until you work out the balance. Another source, can't remember who it was, but more than one has said this, wrote that you can use the plants' response to tell you if more or less is needed. This is a bit tricky, admittedly, until one becomes experienced.

Someone mentioned the minimal macros in Flourish Comprehensive. This product is not intended as a full-source nutrient provider. As the name suggests, it is intended to "supplement" nutrients in a planted tank with fish. It assumes some nutrients will already be available. Hard mineral nutrients (calcium, magnesium, potassium) are minimal because these will be present in most municipal water supplies; however, for those who like me and any living in the Pacific NW of the USA or SW BC, we have very soft water and the hard minerals in Flourish Comp are no where near sufficient, so we have to add them. Concerning other nutrients, the only ones not included are oxygen, hydrogen and carbon, all of which occur naturally in the aquarium. And from all this, one can see that Flourish is also intended for natural or low-tech setups.

The amount of Flourish Comp you need to add will depend upon the light, and the tank's biology. Over 4 years now, I have experimented a bit. I am currently dosing Flourish Comp once a week in all tanks, and Flourish Trace once a week. Flourish Comp twice a week worked in all but one tank (algae increased in this tank with twice weekly doses) but since I have been substituting Trace for the second dose, the plants seem better and I am not seeing algae. I do not add any form of carbon, so I have to balance anything I do, including light duration, with the natural CO2.


Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]

Last edited by Byron; 04-20-2013 at 01:32 PM.
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post #10 of 10 Old 04-20-2013, 05:25 PM
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I would recommend following the instructions on both Comprehensive and Trace. No double dosing on the same day. After the last of your plants have been in the tank for two weeks, then test your No3 and PO4 levels before and after a water change and keep a record of the results. This will give you an idea of the nutrient uptake during the week and how much you are adding during a water change. As another mentioned, the fish will provide some NO3 and PO4 and this will help you determine if that is enough. The link to a calculator that I mentioned in my first reply will help you determine how much nutrients are in your doses. Just total them up and compare them to the test results before a water change and you will know what the actual uptake is. Also do a search on the Redfield Ratio and he recommends a 10 to 1 application of nitrate to phosphate.
For a low tech tank, 5 ppm NO3 to 0.5 ppm PO4 would be a good starting point. From my experience, if you do not have enough of these two nutrients, then it interferes with the uptake of the other nutrients.
Also if you are adding a dechlorinator at your water change, then wait 24 hours before dosing.

Last edited by rjordan390; 04-20-2013 at 05:33 PM.
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