View Full Version : Fertilization Questions

03-16-2011, 06:50 PM
This may be a bit long, but I'm looking for some thoughts on improving my plants in my tank. I'll try to break it down into sections so its not a giant wall of text.

Available Water Conditions
We live in a water co-op area served by 3 mountain side wells for water. The coop adds NOTHING to the water. (Not flouride, not chlorine, not chloramine.. nothing) They do test for quality and release a report annually to ensure that it does not become contaminated.

Tank History:
Originally I had a 20G-L in the same area and discovered the following issues to be true; plants showed increased need for iron and DIY CO2 was quite effective in that size tank. I used Liquid Flourish and Flourish Iron.

In August of last year, the tank was upgraded to a 65G. At that time I added Eco-complete to my substrate and some Flourish tabs. (I've had a bit of difficulty finding tabs on a regular basis however). Due to the size of the tank and the available space, DIY CO2 is not something I can provide a consistent CO2 output that would be effective for the size of tank I have. While I did try it out, I found that the fluctuating low levels were causing more algae growth and not a significant difference in plant growth and so have moved CO2 to a list of future plans for the next major upgrade.

Current Issues
I noticed about a month and a half ago that my "bleheri" amazon swords (of which I have two) were starting to show holes in the large leaves that would eventually grow larger and look just plain icky. I wrongly at that time thought it was a fish or snail nibbling on my plants; however, in my recent research and observations am thinking its more likely Potassium deficiency.

My thoughts and some Questions:
Because this is a new symptom I believe part of my issues are a result of fluctuations in the trace minerals within the well water that would be seasonally related. In my area the precipitation rate in these Fall to Spring months is in the 5-8 inches range while in the summer months its down in the 1-2inch per month range.

Are there good reliable and reasonably priced ways to test for trace minerals that you would recommend to use as a diagnostic for fertilizing?

Would there be any downside to maintaining the same level of all fertilizer with added trace minerals fertilization? (Meaning is it possible to over Iron or over Potassium, etc your water conditions)

Should I be looking into mail ordering dry ferts and mixing my own or will it have relatively no difference compared to the liquid ferts?

I welcome your thoughts and any links to info I may not yet have uncovered.

03-16-2011, 07:18 PM
I cant be much help here it looks like you know more about the subject than I do.

[QUOTE=Trillianne](I've had a bit of difficulty finding tabs on a regular basis however). [QUOTE=Trillianne]

I can tell you that i get my tabs from rootmedic they work really great and have a good selection. I would check them out.

here is the link: http://rootmedic.net/products-page

03-16-2011, 07:58 PM
There are other even cheaper sources of root tabs. I'm developing a red clay tab myself that is more effective and 1/2 to 1/4 the cost.

Using regular osmocote works also (which conspicuously looks a lot like the contents of some of the pill style root tabs :[ ), just frozen in a small bit of water in an ice cube tray, just enough to get it into the substrate, or stuffed into a pill casing.

As for ferts, dosing dry is much cheaper than liquid. The idea behind EI dosing is to dose a set according to the schedule, then at the end of the week you basically reset by doing a water change.

If you aren't running pressurized co2, then don't hesitate to come up with your own dosing routine. You can cut back on the basic e.i. schedule by half or more, just to see how everything goes.

http://bobstropicalplants.com - he has cheap ferts and even cheaper root tabs if you aren't into the DIY approach. He's going out of town tomorrow though so you may get a delayed response. Best of luck!

03-17-2011, 12:26 AM
How are you making your root tabs. I was steering away from them because of cost but if you DIY for cheap some of the plants in my tank would really like it.

03-17-2011, 05:32 AM
How are you making your root tabs. I was steering away from them because of cost but if you DIY for cheap some of the plants in my tank would really like it.

I'm actually using red clay and dry ferts, both micros and macros, but if you want a simple option just get a jar of osmocote granules from any garden center.

03-17-2011, 06:40 AM
Testing for trace minerals would be difficult. The only things I can think of for iron testing would be using a ferrocyanide reaction and developing your own color chart from known solutions. I would imagine it would be very time consuming and probably inaccurate.

Maintaining the same levels of nutrients could lead to algae problems. IIRC iron is a promoter of BBA. Potassium is usually unnecessary to dose, especially if the salts used for nitrate and phosphate are KNO3 and K2HPO4 which are both fairly commonly used in the liquid ferts.

Dry dosing is way cheaper, and you can use the salts to make your own clones of the liquid ferts if you find dosing that way is easier. 1 lbs KNO3, 1 lbs K2HPO4 and 1 lbs trace(CSM+B or other trace formula) will last a really long time with a single tank usually.

As for your troubles with DIY CO2...adding generators, using multiple reactors/diffusers, and staggering the generators can make it viable for most single tanks. I set up a 120g for a friend using 2 inline reactors, 6 3L generators staggered 3 days apart(2C sugar initially 1C+OJ added after a week) and it's been keeping his CO2 levels stable for over a year.

03-17-2011, 04:35 PM
I am familiar with how I could run multiple generators... but as I said.. I do not have the space at this time to do so in a matter that would be effective. It isn't that I do not know the concept, its that lining up multiple 2L bottles on the floor in the middle of my house and praying that cats and people do not knock them over is not an option I want to pursue.

03-17-2011, 08:57 PM
Dosing Excel is an alternative to Co2 if you want to add one more thing to dump in during your fert routine.

If the price becomes an issue you can get the active ingredient in excel (glutaraldehyde) through medical supply under the name cidex or metricide. They are used to sterilize surgical equipment. The % on the 28-day cidex is about twice that of excel so when I use it I dose half-doses.

There are some stories about excel being harsh on vals and some other more sensitive plants but I've yet to run across this issue while dosing sparingly. I recommend against doing the dosing routine on the excel bottle, as it tells you to do a really large initial dose.
Excel is good in moderation, though.

03-17-2011, 09:50 PM
Yes excel is harsh on vals and yes I have vals.

This was something I did try very briefly until one of my vals turned an awful yellow-brown and I looked into it further. (blush)

03-17-2011, 11:08 PM
I have 4 different val species currently and i've yet to have an issue, although I only dose around half the recommended amount.

I noticed that in higher concentrations excel also makes a good algaecide.

03-17-2011, 11:21 PM
ah, yeah that would be a problem. Have you considered the other diy co2 setups? The acid/carbonate(vinegar+baking soda or vinegar+CaCO3) setup is good because it's easily controllable if you have the sophistication to set up a drip or capillary system. If you've got space for a 5g bucket mycellium is another decent alternative that lasts a long time but doesn't generate nearly as much CO2.

If you want to dose potassium, you could try KCl or K2SO4 which are both fairly easy to get. KCl can be found at health food stores as a NaCl alternative, just make sure its not iodized and pure KCl. K2SO4 can be found in garden centers that carry mineral salt fertilizers for lawns. If your plants are primarily root feeders, using osmocote as jeta said is a good alternative to dosing the water column. Testing for it accurately is nearly impossible without a photospectrometer or a colorimeter.

03-18-2011, 01:11 AM
This is my space:


Where the hoses come out is about one arm width wide between tank and wall and is where all my electrical plugs in.

Long term the plan is to replace this tank with a built in custom tank that fits the ledge and open the space below it to store filter and equipment.

This picture was taken not long after I migrated everything to this tank, so things have been rearranged, new plants added. Because I keep cutting off the ugly holey leaves on my bleheri swords, they are about half that height. Very full but obviously I need to address the issue causing them to not have healthy long leaves as they should.

My questions were not really intended as a "which is cheaper" sort but to see if there is a significant difference between dry ferts you mix and liquid pre-mixed as far as plant growth and nutrient absorption.

03-18-2011, 08:48 AM
My questions were not really intended as a "which is cheaper" sort but to see if there is a significant difference between dry ferts you mix and liquid pre-mixed as far as plant growth and nutrient absorption.

Pre-mixed are just the dry salts in distilled water, so there's no real difference. Cost, storage and control over concentrations(and which particular salts used) are about all that changes using dry salts vs the commercial liquids.

03-18-2011, 05:50 PM
Also with liquids like fllourish comp for example, it doesn't really do a whole lot for NPK (macronutrients) as it's mostly micronutrients. It's in liquid form for convenience, but we end up paying for well over 95% water.

Here's a link to the chemical analysis for flourish


03-23-2011, 11:50 AM
An aquarium iron test kit is available - Seachem labs (I believe) and it measures ppm and works well. A simple "mineral" test would be to boil off a pot of water and see if you get any "powder" - if yes, you have a good bit of minerals, if not , well, doesn't say anything useful one way or the other then.:hmm3grin2orange: