Help Needed - Co2 and High Iron Problem

[drjack]

Hi, I have a water chemisty problem, I think. I have only a year's experience with planted tanks so quite new to this. First here is a summary of my tank:

Tank: Juwel Vision 180 with 125 litres/32 US gallons water.
Lighting: Medium - 2x35W T5 tubes 8 hours/day = 0.6 watts/litre or 2.2 watts/US gal
Substrate: Caribsea Eco-Complete
Filtration: Juwel supplied Bioflow 3 internal plus Eheim Ecco pro 200 external
CO2: D-D Pressurised CO2, CO2 approx 25ppm, Bubbles/Min = 115

Test Results:
Temp 23.4oC , pH 6.7 , Ammonia 0 , Nitrite 0 , Nitrate 10, GH 6.7 , KH 3.9 , PO4 1.0, Fe 1.5, TDS = 187

Easy Life ProFito – Just migrated at 13 ml/week (Easy Life say I can increase to double). Adding Seachem Nitrogen as needed.

Fish 28
1xCory , 2xOtocinclus , 2xChain loaches , 6xRasboras , 10xCardinals , 3xWidows , 3xShrimp , 1xPlatty

Plants ~ 125
45 Crytocoryene Lucens, 1xEchinodorus Schleuteri Leopard, 1xEchinodorus Red Special, 2xEchinodorus Aquartica, 36xLudwigia Repens Rubin, 3xHygrophila Pinnatifida, 2xAponogeton Crispus Red, 14xEleocharis Parvula, 2xAnubias Congensis, 4xVallisneria Spiralis, 12xLimnobium Laevigatum

My Problem:

I am not adding Iron but my Fe test result is very high and I do have some algae on the glass. So where is it coming from? The test kit is okay. I spoke to someone with a chemistry background and they said without any knowledge of tanks, are you adding lots of CO2 - it could be pulling iron from your substrate. My substrate is EcoComplete and Iron rich and I have felt my Co2 bmp is too high. The calculation based on volume and Kh says by bubble rate should be about 12 bpm, but at that rate I get BBA. Now it seems, with 112 bpm I could be causing too much iron to enter the water column.
I feel I am in a catch-22. I get BB algae so I add more CO2, by adding CO2 I get high iron and more algae.
Does anyone know if the CO2 explanation sounds right? Also, what bubble rate should I really be using? Is 112 bpm okay or far too high - the plants are not pearling and the fish look happy. Also, I know there is a relationship between Lighting, CO2 and Ferts but with 2.2wpg do I also need to be careful about adding too much CO2 because I do not have high levels of light?

Really struggling, any advice really appreciated.
Cheers, David

 

[ceg4048]

Hello,
First of all, Iron does not cause algae. Second of all, Iron test kits are NOT OK. They along with most of your other test kits are rubbish and their results cannot be trusted. Thirdly, the commercial range of nutrient product are so weak that you normally need to add at least twice or more of the bottle dosing recommendation.

The combination of these items means that you have essentially built a house of cards. It is not a good idea to run a high tech tank using test kits. They will inevitably lead to problems. Did I mention that nutrients don't cause algae? If you have an algal problem it is more correct to assume that you do not have enough of some nutrient. It is also likely that you have a flow/distribution problem which exacerbates any nutrient shortfalls.

You have not identified the algae on the glass. It is highly likely that this is GSA which results from insufficient PO4. It's also very likely that your PO4 test kit is lying to you. As you increase the CO2 the demand for nutrients increases. These are classic symptoms of the yo-yo effect in a high tech tank.

If your flow/distribution is poor for the given lighting level then the first casualty is CO2 uptake so you are forced to inject at a higher CO2 rate, however, adding more CO2 generates a higher plant metabolism, so they have to gather and consume more nutrition to satisfy this increased metabolism. If this higher nutrient demand is not met, the plants weaken and algae attacks.

Therefore, you do not have a water chemistry problem. You have a test kit problem and an algae problem driven by malnutrition. You also probably have a flow/distribution problem. You should try to adhere as much as possible to the 10X rule, so that you have 180L X 10 = 1800 Liters per hour total combined pump rating. The pump effluents should also be carefully arranged so that they act cohesively.

Cheers,

 

[drjack]

Hi, Thanks you for the reply. I thought I had 1 problem but now .... Could I ask a few more questions for novice guidance please.
Test Kits - If my JBL iron test kit seems consistent for example with RO water it says it contains zero iron (zero iron in RO water is correct) but in my tank it says 1.5 on what basis threfore do I conclude it is lying to me? How do I therefore know that any test kit is any use. All the guidance says do tests every week. Now you say all tests lie to you - so what's the point? What do you recommend I do?
CO2 - If the formula suggests and in one of your articles (Co2 using a drop checker) you suggest an initial CO2 bpm rate of about 12 for my tank (120 litres water). Then is 112 bad? Should I be trying to get it back to nearer 12?
Iron/Co2 Chemistry - It seems from what my chemist friend told me that increased CO2 will cause iron to be pulled from the substrate. Do you agree? As I have increased my bubble rate to attack BBA my iron test results have gone up with each increase. Coincidence? I have also read in numerous places that high iron can cause algae.
GSA - I am sorry I didn't mention this, but "Yes" I believe it to be GSA. I know GSA can be caused by low PO4 or low CO2 or high lighting. I am assuming my lighting is not classified as "high" based on what I have read. So I can increase PO4 but what about the CO2 - my levels seem okay based on the drop checker but I am worried about the bpm - 112 seems such a long way from 12 but could it to be too low?
Flow/distribution - I am doing what I can with spray bars. One along the entire back of the tank and one along the side. This would imply the are not working together but I can adjust each half of the spray bar and the plants do obstruct the flow but I can see plants moving in all corners so I have to assume the flow is as good as I can get it. But if I need to improve this what can I do, I have heard of Koralia pumps would that be worth considering?

As a newcomer to this, what is really frustrating is all the contradictory advice. It's enough to make you want to give up. Regards, David

 

[ceg4048]

Test Kits - If my JBL iron test kit seems consistent for example with RO water it says it contains zero iron (zero iron in RO water is correct) but in my tank it says 1.5 on what basis threfore do I conclude it is lying to me? How do I therefore know that any test kit is any use. All the guidance says do tests every week. Now you say all tests lie to you - so what's the point? What do you recommend I do?

Hi David,
The problem with test kits is their inconsistency and their lack of a linear response. This is why the folks who like to use test kits defend their use by employing a calibration. In this calibration, RO water is mixed with varying amounts of a known amount of the solute and the then tested. The readings are plotted on a graph which generates a curve. As the concentration rises, the readings of the kit can be seen to vary, and the variation from reality changes. For test kits that use a powder for a reagent, a simple change in humidity affects the readings by importing water into the powder, changing it's chemistry. The result is that even a calibrated kit will have a different response curve on different days. Most kits simply can't be trusted. A reading of zero in RO water cannot tell you what happens as the concentration increases.

As I mentioned in my previous post, most test kits are entirely irrelevant because it is not necessary to maintain some set values of nutrition. All one really needs to do is to avoid being below the minimum concentration value for nutrients. If you exceed the nominal values the result will simply be that the plants will grow faster. If you are below the nominal values the risk is failing plant health due to malnutrition. If you are dosing a certain amount of nutrients then you know exactly how much you have put in he tank. Since you only have to maintain the value above the threshold value you are i complete control so there is no need for test kits. The test kits have you hypnotized into thinking that they are better for you than your eyes. The plants are your test kit. If thy re suffering and if they have algae then you know you have a shortage of something so you'll need to add more. We already know what shortages of nutrients cause what symptoms. Therefore, if you see the symptoms then you know what is missing. This is something that a test kit cannot tell you.

CO2 - If the formula suggests and in one of your articles (Co2 using a drop checker) you suggest an initial CO2 bpm rate of about 12 for my tank (120 litres water). Then is 112 bad? Should I be trying to get it back to nearer 12?

Well, 2 bubbles per second may or may not be a problem. It's impossible for anyone to predict how much CO2 is required for any tank. Again, the plants will confirm this. That is a simple illustration of my first point above. When you are below the nominal injection rate then the plants suffer and you got algae right? No test kit readings could have given you a better indication. Yet, somehow you decided reject this method for the other type of algae. The 112 would only be bad if it causes a problem for your fish. This does not mean however that you cannot improve your distribution. I have only assumed that you possibly have poor distribution. But this is only a statistical assumption (most people have poor flow). I do not know if that is really the case for you...yet.

Iron/Co2 Chemistry - It seems from what my chemist friend told me that increased CO2 will cause iron to be pulled from the substrate. Do you agree? As I have increased my bubble rate to attack BBA my iron test results have gone up with each increase. Coincidence? I have also read in numerous places that high iron can cause algae.

Well, The typical behavior of Fe in a tank is to precipitate out of solution and to form compounds with poor solubility. There is no direct reaction of CO2 with Fe, however, CO2 reacts with water to form Carbonic acid. This results in a higher concentration of Hydrogen ions (H+) and this can increase the solubility of precipitates. Iron takes two well known ionic species when dissolved - Ferrous; Fe++ (Iron II), and Ferric Fe+++ (Iron III). These are known as the "Oxidation States" which just means that they have different electrical charges and therefore have a different reactivity with other charged particles. Adding an acid to the water generally reduces the Fe+++ to Fe++ (Ferric==>Ferrous which has a higher solubility). So a test kit reading may or may not be affected depending on which form the kit is sensitive to, which salts the Iron formed and the relative solubility of each. That's the problem with test kits. It's never clear what chemicals are in the reagents and what tricks of nature can fool them.

GSA - I am sorry I didn't mention this, but "Yes" I believe it to be GSA. I know GSA can be caused by low PO4 or low CO2 or high lighting. I am assuming my lighting is not classified as "high" based on what I have read. So I can increase PO4 but what about the CO2 - my levels seem okay based on the drop checker but I am worried about the bpm - 112 seems such a long way from 12 but could it to be too low?

Well, I mean, just add more PO4 and don't worry about how many bubbles you have. It's that simple. When you add more CO2 you need more of everything else. PO4 actually improves the uptake of NO3 so you might even find after adding more PO4 that you need to add more NO3. So the added CO2 solves the BBA and the added PO4 solves the GSA. What could be easier, and why would you need to test for what you just added? Double your PO4 and wait three weeks to see what improvements it made.

Flow/distribution - I am doing what I can with spray bars. One along the entire back of the tank and one along the side. This would imply the are not working together but I can adjust each half of the spray bar and the plants do obstruct the flow but I can see plants moving in all corners so I have to assume the flow is as good as I can get it. But if I need to improve this what can I do, I have heard of Koralia pumps would that be worth considering?

The rule of thumb is to have all the effluent "pulling together" and pointing in the same direction. Try moving the bar that is mounted on the side to a location just above or below the bar along the back. Assuming that you have covered the entire length of the tank that should work fine as long as you have sufficient flow rating. Point the holes in a perfectly horizontal orientation.

As a newcomer to this, what is really frustrating is all the contradictory advice. It's enough to make you want to give up.

Well, yes it is frustrating, but we have collected enough evidence here to know what works and what doesn't. Test kits don't work. Worrying about excess Iron due to CO2 doesn't work Paying attention to flow, CO2 (as well as diffusion technique) and maximizing nutrition all work well. You may want to think about using the dry powders as a cheaper and more effective dosing method than the commercial mixes.

Cheers,