Tropical Fish Keeping - Aquarium fish care and resources

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redchigh 01-06-2011 11:54 AM

potassium deficiency or snail nomnoms?
In my 10 gallon Central American, I have an E. Bleheri var. Compact that seems to be having some problems.

The older leaves have holes. The part of the leaf surrounding each hole looks brown and soft, but the rest of the leaf is perfectly healthy.

I use soil, which is generally high in micronutrients, but may not have enough potassium... I have no idea which it is. (I may start dosing with potassium anyway to see- I plan on dosing with saltpeter- potassium nitrate.)

So, I'm going to trim the old leaves off, but does anyone know whether it's snails or nutrients?

I know EI nutrients are pretty powerful stuff- I think I'm going to dose about 1/16th of a tsp to start.

Byron 01-06-2011 01:11 PM

Probably nutrients, but can you post a photo?

redchigh 01-06-2011 01:40 PM

I don't have a camera right now, but I can try tonight.

Well, here's a pic I found online. My holes look the same.

Byron 01-06-2011 06:40 PM

I have had the same, now and then. Increasing Flourish Comprehensive to twice weekly causes this to disappear (in new leaves). As you know, I am not a fan of dosing individual nutrients because the plants respond better when everything is balanced, and adding this or that can make it worse. Also some problems can have more than one nutrient deficiency.

SinCrisis 01-12-2011 10:17 AM

a quick fert question, sorry if its a little off topic. Byron, wouldnt dosing a comprehensive fert create an excess of nutrients that are not lacking in the tank? for example, if mineral A was lacking but mineral B is not, dosing both A and B would create enough A for the plants but then there would still be an amount of B that is not used and just sitting in the tank. Wouldnt single minerals be more effective here in achieving a balance?

redchigh 01-12-2011 10:30 AM

Well, if we had expensive test kits to test everything, then we would know what to dose.

EI dosing uses a similiar premise- it purposefully doses more nutrients than the plants can use, but as long as the nutrients are balanced, algae won't take hold.

Plus adding nutrients to the water column shouldn't change much- soil tanks don't have hardly any nutrients in the water. They force plants to get it from the substrate. (Why many of my stem plants have 4-inch roots.)

Byron 01-12-2011 12:43 PM

SinCrisis, to answer your question, no. One has to keep in mind the various nutrients. Plants do not require very much of any one of them, and they must all balance the light. This is why, in a low-tech natural system, a comprehensive fertilizer is considerably more economical--it takes so very little.

First, a comprehensive fertilizer like Flourish does not have so much of any single nutrient that overdosing of this or that nutrient can occur, because it is highly unlikely sufficient amounts of any one nutrient will be available in the aquarium from other sources. At least, not those that could cause trouble (iron, copper, manganese, etc). Even most fish foods today do not contain much potassium [or is it phosphorus, sorry, memory blank out] that is said to cause algae troubles. And most water supplies have limited if any heavy metals (iron, copper, zinc, manganese, nickel) and we use water conditioners that detoxify these anyway.

Second, some plants can store a limited amount of nutrients. Slow-growing plants do this, like crypts. And here again, the "excess" is not likely to be that great.

Third, plants detoxify metals. There is obviously a limit to this, but they do it, along the same methods as the water conditioner. We call it "taking up" as opposed to assimilation. Plants assimilate copper as a nutrient, but in excess they take it up and thus detoxify it.

To the next point made by redchigh, we would indeed have to test for every one of the 17 nutrients, and that is not only laborious (and well nigh impossible for those of us without scientific equipment for so many of the micro-nutrients) but un-necessary. Nature has a way of balancing things, provided we do not tip that balance. Which is one reason I do not adhere to the EI method. First, I can't understand the logic of dumping nutrients into the tank and then doing a massive water change to remove some of them, which is the basis of the method. This is much more likely to create the problems mentioned in the initial question.

Last comment on nutrients in the water versus soil. Plants can only use nutrients dissolved in the water--they cannot assimilate nutrients from soil. The nutrients in the soil must get into the water in the substrate in order for the plant roots to assimilate them. The same works in land plants, which is why hydroponics is so successful [terrestrial plants cultured in water without any soil]. The soil is simply the storage place of the nutrients. But the nutrients can just as well be added to the water column to make their way down through the substrate (if it is not compacted) and thus be assimilated by the plant roots. And of course there are plants like floaters and non-substrate rooted plants that have no use of the soil or any substrate at all as far as nutrient assimilation is concerned.


redchigh 01-12-2011 02:35 PM

If I decide to go with weekly dosing, then I'll probably use something similiar to flourish.
(Homemade flourish, with dry ferts.)

Well, the EI relies on a weekly waterchange... Then again, don't most people do those anyway?
I definately wouldn't use flourish and trust the soil mechanics... If I dosed flourish, I'd do a w/c once a month... Even with flourish, 6 months without a w/c might have some unwanted side effects.

SinCrisis 01-12-2011 03:33 PM


So this means that event hough mineral B (still referencing my example) is in excess, the plants will "take it up," but just wont utilize it immediately?

But at some point, lets say, the tank is lacking in iron, but has an excess of potassium. Adding a comprehensive fert like Flourish would add both iron and potassium to the tank. The plants, needing iron would utilize it right away along with the ratio of potassium that it can use, but at some point wouldnt the plants stop being able to use or take up excess potassium due to not enough iron in the water to help it and the mineral would just build up in the water until a water change is done wouldnt it? <-- I dont know if im articulating my question correctly.

I thought plants would need to absorb a certain ratio of minerals and nutrients? IE if theres a certain amount of mineral A then only a certain amount of mineral B will be used. The plant cannot just utilize everything in the water right?

I understand that testing for everything is expensive and excessive in most cases, but im just wondeirng if its good for the long run?

Byron 01-12-2011 06:38 PM


Originally Posted by redchigh (Post 557891)
If I decide to go with weekly dosing, then I'll probably use something similiar to flourish.
(Homemade flourish, with dry ferts.)

Well, the EI relies on a weekly waterchange... Then again, don't most people do those anyway?
I definately wouldn't use flourish and trust the soil mechanics... If I dosed flourish, I'd do a w/c once a month... Even with flourish, 6 months without a w/c might have some unwanted side effects.

Your use of the word "relies" is my point, and my concern. Deliberately dumping stuff into the tank knowing that it needs a water change to sort it out and prevent trouble is to me not wise. Doing a water change to handle natural biological issues is "natural," because we have no other way of replicating nature, although with enough plants and a fish load that is in balance water changes do not need to be done. Ms. Walstad suggests one every six months, no more, but at the same time she stresses that she has a minimal fish stocking to make this work.

I'm going from memory again, but I believe Ms. Walstad's method uses no added fertilizers (?). I am skeptical of this too, long-term.

In personal communications with Tom Barr, we discussed water changes, and he was quite insistent that they were un-necessary in low-tech systems and I would have better plant growth without them. He did advocate them in high-tech with EI dosing of nutrients.


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