Fertilizer Recommendations & Info - the Informal FAQ

Hey guys,

Not sure if i missed something but I read through the topic and still have a few questions. How much nitrate do you guys shoot for. I have a decently stocked 55 gallon with plants and my nitrates are just under 5 ppm. Too low? Too high? Also I am currently using kent freshwater plant and kent pro plant. Does anyone know how these stack up? I know for a fact that they do not contain any nitrate or phosphates like the original post suggested having. So i guess my question is, if im using these two feralizers, what else would I need in addition for healthy plants? More nitrate? more phosphate? Doesnt phosphate promote algee growth though, or do the plants soak it up before the algee can get at it?

And with the nitrates, Im planning on stocking cherry shrimp which are very sensitive to nitrates. Anything over 10 would be too much for them.

Going off the top of my head because i not currently at home I believe that my fertalizers do have Potassium, magnesium, and iron, which were mentioned in the first post. As well as some other stuff. Again im not sure as i dont have the bottles readily at hand. I also have a bunch of DIY co2's setup for carbon. PH is about 7 and KH is about 5-6 so that comes to a bit under 20mg/l of CO2. I read this is a good level to have it at for your plants without harming fish. True? False?

And if it helps any I have about 4.5 watts per gallon. Compact flourecents at 6700k. And i have an R/O unit that I run all my water through. After i add kent r/o right and ph stable.

Many questions I know.. Thanks for any help in advance though.
 
Well, first of all, why the RO? You're spending a lot of time and money to (essentially) take stuff out, then spending some more money (RO right) to put it back.

Secondly, how are your plants growing? Generally, I shoot to keep my NO3 level between 10 ppm and 20 ppm. However, if your plants are growing well and you don't have any algal problems, I'd say don't change a thing.
 
happychem said:
Well, first of all, why the RO? You're spending a lot of time and money to (essentially) take stuff out, then spending some more money (RO right) to put it back.
Click to expand...

you are correct, however the ro unit is more for the fish and less for the plants. I have sensitive fish like clown loaches and so I got the ro unit to get all the crap out, and as you said, in turn takes out all the good stuff too. So i need to put that all back in.

happychem said:
Secondly, how are your plants growing? Generally, I shoot to keep my NO3 level between 10 ppm and 20 ppm. However, if your plants are growing well and you don't have any algal problems, I'd say don't change a thing.
Click to expand...

Plants are growing good but seems to be a little slow. I guess im not really sure how fast they are supposed to grow in perfect conditions anyway. Many of the plants i got for free and thus dont know the names of most of them. The ones i do know i have are an amazon sword, and some anubius. I do know that the anubius are supposed to be slow growing plants, but so far i have seen no growth from them at all in a three week period. is that normal for them?

otherwise algee seems to be very much in check.
 
Last edited:
What is in your water that is so harmful to loaches? Have you tried keeping them on tap water?

At your light level and with presence of CO2, bottled fertilizers aren't adequate at the "recommended" dosing levels, especially since you've removed any usable elements from the water to begin with. Double or even triple the doses recommended would be a good start.
Yes, nitrates and phosphates...the plants need them. I always had good luck sticking to 5ppm Nitrates/.5ppm phosphate using "medium" lighting. I think with higher light, you'd want to go higher. I recently upgraded lighting so am now shooting for 10ppm/.1ppm and I keep Cherry shrimp.
 
I was reading over this sticky in search of info on the 2 Kent ferts mentioned, but it appears mostly everyone here does there own. One of the plant guru guys at the lfs here has an awsome plant tank and keyed me in on the kent ferts. I am just started them this week. FWIW I will post up the specs.

Kent Freshwater Plant 0-0-3
K2O 3%
Cu .00001%
Fe .24%
Mn .01%
Mo .0009%
Zn .00014%

Kent Pro Plant 1-0-0
N 1%
B .0002%
Mg .05%
S .06%

The recomended dose is 5-15ml/1-3tsp per 30gallons for each (they are meant to be used together). Niether contains no phosphates. Also says "Do not use more than twice the recommended dosage". So the two combined would be like 1-0-3 I guess.

I also ordered some flourish excell since so many here use it... dont know if I am going to use it also on my co2 tank or just one the couple that I dont have co2.

BTW blackthorne, I have 3 clowns and they have done just great with city water... even been through a few months of not changing the water (thanks to my former job working me to death lol). But I suppose the best water would be pure r/o water with only exactly what you need put back in. If you do this, then I guess more power to you :thm: but for most it might be unecesary.
 
try measuring.

I am new to this site, and was reading through this thread. I found a number of posts made me laugh, while others disturbed me.

One of the most frequent questions I noticed was on how to know how much of or if add something. I was especially shocked by the responses that seemed to say "don't worry about it just add it without reguard to amount".

For those that are new to fertilizing, I suggest you start simple until you learn more. Stick with premixed aquarium fertilizers that contain Potassium, Iron and trace elements. Unless your using purified water these are the items you are most likely to be deficient in, at least at the beginning.

Now to figure out what if anything else you may need. Look at your plants, are they growing well? If so stop here, if not continue on. I recently read a very good way of determining this, take a picture of your tank today and another a week or two from now and compare the difference.

Start with one nutrient at a time and research it on the various websites or from books. Try to learn what most sources agree upon as an ideal level, as well as what is considered too high or low. Also try to learn what the effects of too much or too little of a nutrient are.

I suggest measuring your tank conditions if possible with a test kit before and after a water change. This gives you a starting and ending value to determine a rate of change if any.

I'll use the example of Nitrate, since it was mentioned in the other posts and most of hobbiests eventually buy a test kit for it. Lets say that we did the research and determined that 10ppm was ideal with 20ppm getting a little too high and 5 ppm getting a little too low.

Now first example lets say that we measured 20ppm right before a regular consistant 50% water change and 10ppm right after the water change. We now know that the Nitrate level is increasing from 10 to 20ppm between water changes and that the water we are adding isn't adding any additional nitrate to the aquarium. This also tells us there is no need to add nitrate to the aquarium because it is already there in an adequate amount.

In the second example suppose we measured 0 ppm before the water change and 5 ppm after the water change. This tells us that the nitrate level is decreasing between water changes and that the water we are adding contains a small amount of nitrate. This also tells us that we need to increase the nitrate level. How much do we add?

Well if we purchase a good brand name aquarium fertilizer the directions will tell us. Something like SeaChem's Flourish Nitrogen's directions state to add 2.5ml per 40 gallons to increase Nitrate 1ppm. If we didn't purchase something with good directions or went the DIY route, all is not lost, we can can figure out how much to add using our test kit. As mentioned in another post you can add a small measured amount to a gallon jug of water and measure it with the test kit to see how much it increased. We may have to dilute it with more water or add more nitrate to the water if it is not within the range of our test kit.

A word of caution, not all fertilizers are compatible with all test kits. Make sure that what you are measuring is the same thing you are adding. I had a Red Sea Iron test kit and tried this test using SeaChem's Flourish Iorn. No matter how much Flourish Iron I added to the water the Red Sea test kit always read zero. I later learned that the Red Sea test kit measured chleated iron and that SeaChem used something other than chleating agents to keep the iron usable to plants. To resolve this I purchased SeaChem's Multitest iron as suggested on the bottle of Flourish Iron and the problem was fixed.

Now for the example of what if there is no test kit available or the test kit is too expensive. This is where the last part of our research comes into play and that is knowing what the effects of too much or too little of something are. Keep in mind that "MOST" water sources that are considered safe to drink are relatively low in nutrients. Also keep in mind that fish waste produces some Nitrate, Phosphate and possibly Potassium.

Our research tells us that excess nutrients like Nitrate and Phosphate can cause problems so they should only be added with extreme caution if your not measuring because your taking a risk and falling back on much less reliable trial & error. On the other hand our research tells us that excess nutrients such as Potassium are relatively safe and do not cause any problems at reasonable levels, so you should be able to reason/calculate the amount to add to bring your tank to ideal levels. If some was already present in your aquarium and you added enough for your plants on top of it you should still be safe.

Please do not just accept the values I used as examples as the "right" amount for your aquarium but instead research and compare what those who have been getting it right for many years are doing. Many of them disagree upon the exact right amount, but if you choose a happy medium you probably won't go wrong.
 
While I do not disagree with the general sentiment of process detailed in your post (it was very well done), I suggest you update your research somewhat. Excess PO4 and NO3 are not the cause of algae, despite older references stating that they do. Test kits, while a good idea, are not strictly necessary. That said, I prefer kits to no kits. Dry ferts can be weighed accurately and the concentration provided by adding a given mass can be calculated easily.

On a side, and less important, note, there are only three ways that come to mind to keep iron in its 2+ state: chelates, strong acid, and anoxia. The last two are simply impractical. Hence, I'm very interested to find out where or how you learned that Seachem uses something other than chelates to stabilize their Fe(II).
 
Here is a link to one of the references I found about Flourish Iron.
http://www.thekrib.com/Plants/Fertilizer/flourish.html
Not being a chemist, I don't really understand how it works, but it has gotten a number of recomendations, from very experienced hobbiests, whos advice I have grown to trust.

I am a little biased when it comes to measuring, I'm a metrologist and measure things for a living. For me it's all about attention to the details.

As for my research being out of date that is quite probable, I tend to look for info from those who have been getting consistant great results for many years as opposed to those that only tried something in the short term. But because the older info has been around longer than I have, it is much more widely spread than the newer info.

Oh the bottle of Flourish Iron reads:
"Flourish Iron™ is a highly concentrated (10,000 mg/L) ferrous iron (Fe+2) gluconate supplement. It should be used in those cases where the iron requirements exceed that which can be delivered by Flourish™ at the recommended dose or signs of iron deficiency appear (such as short and slender stems or yellowing between veins.) Plants are able to much more easily derive a benefit from Flourish Iron™ than from EDTA-iron sources because all EDTA iron is in the ferric (Fe+3) state. Since plants require iron in the ferrous state, additional physiological energy must be expended in order to extract the ferric iron from EDTA-iron and then convert it to the ferrous form. Contains no phosphate or nitrate."

"DIRECTIONS: Use 1 capful (5 mL) for each 200 L (50 gallons*) or as required to maintain about 0.10 mg/L iron. For smaller doses please note that each cap thread is about 1 mL. Use MultiTest: Iron™ test kit to monitor iron concentrations. Use as needed to combat signs of iron deficiency (usually seen in new growth) which include: chlorosis (yellowing) of tissue between veins and short and slender stems."
 
Last edited:
Thanks.

The gluconate is a chelate, just not in the traditional sense that one usually thinks of chelates. Basically it's just a big (a statement open to interpretations) organic molecule which binds the metal and keeps it in its 2+ state.

I'm keen on measuring stuff myself - being an analytical chemist turned chemical oceanographer (which is really just analytical chemistry on a ship ;) ). However, I'm also a little leery of the reliabilities of them. I've prepared the same reagents used in the kits for nutrient analyses in the lab, our references state that the reagents are useable for at most a couple of months. Granted we have a much greater need for precision and accuracy than the hobbyist, but it does leave me a little skeptical as to the reliability of the readings from my kits - especially since the kits probably sit in a warehouse for a couple months before making it to my home. I can standardize most of my kits, most folks either can't, or don't, but if one is going to rely on them, standardization is a must. But this is coming from an analytical chemist, sometimes I get a little lost in the details myself. :D

As for the research, I hear ya. Check out the Barr Report (www.barrreport.com/). Tom Barr has done, and continues to do, very good and rigorous research. It's well worth the $15 price of subscription.
 
You must log in or register to reply here.
AquariaCentral.com
Top Bottom