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Discussion Starter · #1 ·
I set up a 30 Gallon Walstad style tank a year and a half ago and everything was going great! My plants flourished with the 4x12W submersible florescent lamps. Over time, the submersible lamps burnt out/short circuited (probably due to water that eventually seeped in) so I removed the last remaining lamp and replaced with 2x 24W CFL lamps 10cm from the surface of the water.

I also added floating plants and riccia (floating) to cut out some of the light and reduce the PAR reaching the plants at the bottom.

Recently I have noticed that my plants are not doing so well; after a major death spree in my tank after medicating for an infestation of intestinal nematodes introduced by QT'ed fish that previously showed no symptoms, plant growth has been stunted. I assume the floaters (ceratopteris cornuta, lemna minor and pistia) and riccia suck up the majority of the nutrients... I think nitrates are particularly lacking since I have noticed string form blue-green algae on the undersides of some pistia leaves. The two plants most affected were E. Azurea and Ludwigia. Also, tiger lotus, anubias and java fern growth has stalled completely; with holes appearing in the leaves of anubias and java fern.

The thing is, despite using RO (9 micro siemens) water to top off the evaporation and keep Gh, Kh and pH levels constant, my TDS and EC are constantly increasing. I do not have any oyster shells in the substrate (although I do have a large malaysian trumpet snail population) and I have bogwood to soften the water. The water pH is 5.5 but the TDS is currently at 450 ppm! And Here I was, wondering what had happened to my Sakura Fire Reds!

OK so I guess my problem is two fold:
1. stunted growth of plants; this may be explained by the presence of floaters
2. Rising TDS and EC levels (don't have a Gh kit but expect that this has risen too as it is connected to TDS), despite presence of natural softeners (bogwood, catappa leaves).

Any thoughts as to what I am doing wrong and what I can do to correct it?
 

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I would like to know what you are using to fertilize your tanks water column?

Anubias, Java fern, and tiger lotus are all very aggressive consumers of nutrients in the water column. This is why most people place anubias and java species on hardscape. They have adapted to do so and if you are not placing anything into the water this is probably why you are seeing deficiencies in these plants.
 

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Discussion Starter · #4 ·
Is "slow growth" what you mean by "stunted"? Plants adapt to their environment.
Hmm, well I did not mean slow growth but perhaps "much much slower" growth is the appropriate word. Let me put it this way: the lotus leaves have mostly melted away and it hasn't put out any new leaves in over 2 months.

Bump:
I would like to know what you are using to fertilize your tanks water column?

Anubias, Java fern, and tiger lotus are all very aggressive consumers of nutrients in the water column. This is why most people place anubias and java species on hardscape. They have adapted to do so and if you are not placing anything into the water this is probably why you are seeing deficiencies in these plants.
I am not dosing the water column with anything. As I understand it, that is the whole point of the Walstad method, is it not? No water changes, no fertilizers, no co2?
 

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But are you using any additives to the water??? The water coming out of the RO would be too low in nutrients to support any plant, and pin holes in old leaves is be associated to deficiency of Macro elements . As for as Walstad method goes I'm sure use of RO water is nowhere recommended.
 

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Discussion Starter · #6 ·
But are you using any additives to the water??? The water coming out of the RO would be too low in nutrients to support any plant, and pin holes in old leaves is be associated to deficiency of Macro elements . As for as Walstad method goes I'm sure use of RO water is nowhere recommended.
The Walstad method advocates no water changes.

I thought it was clear that I was topping off the evaporation (which is pure H2O) with RO water (which is as close to pure H2O as you can probably get, save perhaps using rain water instead). This was water out is replaced by (almost) the same water in, hence there are no Gh, Kh or TDS swings (and pretty much the same as no water change).

I never said I used RO water when setting up the tank; had I done this, you would have been correct and the water would have been pretty much uninhabitable by most plants. I used regular tap water mixed with a brand name bottled drinking water (to get the desired GH and KH vaşues) when setting up the tank; this along with the dirt in the tank should be sufficient for plant growth. Having said that, you may be right on the macro elements issue, as these may not necessarily be present in the soil used.

None of what you said explains the TDS rise though...
 

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I would use your tap water for top offs. Although natural bodies of water maintain a fairly stable GH and pH annually there are still periods of pH/GH fluctuations during dry/rainy seasons. The fact you aren't doing water changes(not saying you should) is contributing to the rising level of TDS. I top of my Walstads weekly and have flourishing plant growth. All I do to my water is treat it straight from the tap. Then let it sit for about thirty minutes. The only time I do water changes is if I see some algae that sticks out like a sore thumb. I do this for all three of my Walstads - little to no visible algae, no pinholes, lush growth, healthy livestock. Weekly top offs with dechlorinated tap water.
 

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Discussion Starter · #8 ·
I would use your tap water for top offs. Although natural bodies of water maintain a fairly stable GH and pH annually there are still periods of pH/GH fluctuations during dry/rainy seasons. The fact you aren't doing water changes(not saying you should) is contributing to the rising level of TDS. I top of my Walstads weekly and have flourishing plant growth. All I do to my water is treat it straight from the tap. Then let it sit for about thirty minutes. The only time I do water changes is if I see some algae that sticks out like a sore thumb. I do this for all three of my Walstads - little to no visible algae, no pinholes, lush growth, healthy livestock. Weekly top offs with dechlorinated tap water.
Thanks for the comment. Just a couple of questions if I may?

1. I guess TDS is a little different from KH and GH, because I would have thought not doing water changes and topping off with reverse osmosis water would keep all the values constant.

2. How do you treat your tap water? If you are referring to the dechlorination, I usually let the water sit for a week before use.

3. If you top off weekly with tap water, you should have constantly increasing KH, GH and TDS levels?
 

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ph is too low

 

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Great cahrt OkeyDokey! I meant to mention OP's pH in my post. Going back and re-reading your OP. Why are you intentionally trying to acidify/soften your water? Most aquatic plants come from at least slightly acidic waters but thrive, if not "do better" in water with moderate hardness(due to the availability of more trace elements in higher GH waters). Do you have a copy of "The Ecology of the Planted Aquarium"? If not get a copy. If you do have a copy - re-read it. I've read mine several times and the more you read it the more you realize you missed or, refresh on things you have forgotten/didn't understand the first go around.

1. Though they are related these values are not the same. No, just topping off does not keep the values "the same." As I said, you are constantly INCREASING your TDS by NOT removing anything - only adding to your TDS. Using RO(pure H20) is not adding anything(Macros/mricros). With RO you have 0GH, and 0Kh(I do not know how pH is affected by RO - I don't use it nor have I ever. I'm not against it I've just never used it or read a lot on it). With a 0Kh you have nothing buffering your tank water ie. your water is constantly acidifying. The presence of carbonates in your water(KH) prevents/slows the constant acidification of aquatic environments. You may want to do some reading on what GH and Kh values reflect and how they affect aquariums as a refresher.

2. Yes, I use dechlorinator. Does RO remove chlorine/chloramine(like I said, I don't know)? Why are you letting it sit for a week?

3. No, KH, GH levels are constant (possibly a few degrees of fluctuation at occasional water changes - not enough to notice a difference in my regents).. I don't test TDS but, yes, I'm sure they rise to an extent but should only reach a certain level before leveling out. However, in a healthy Walstad system there should be an equilibrium attained at which point everything should balance itself from uptake/input by plants(uptake) and fish/keeper(input) thus resulting in constant Gh, pH, KH.

I'm sure I've left out some information and maybe added to confusion. Hopefully some one can explain better. In short. Start topping off with dechlorinated tap water you should see more growth soon. Also, try raising your KH and pH, remove the almond leaves. Or, simply add something to raise your KH(baking SODA, oyster shells), this will increase your pH at the saem time(different rate). Do a Google search for raising/maintaining KH in aquariums.
 

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I use Walstad method in 4 tanks. 3 tanks have TDS in 300ppm range. These 3 tanks are dirt capped with sand. Another thank has TDS over 1000ppm. This tanks has just gravel. I would say all plants grow fine. I don't do water change. Top up only. Tanks are 8+ months old. I found that I need to add potassium and iron. According to Walstad book, both elements are in too low concentration in most fish food to provide sufficient nutritents to plants.
 

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Perhaps this is a good chance for me to learn something here.

I was under the impression that if you topped off with RO water that the Gh and Kh would stay consistent, but that if you topped off with tap water you would be adding to the water column some things which plants won't absorb/eat/uptake and as a result, over long periods would see larger and larger amounts of minerals in the water, contributing to a very large TDS I would assume.

I mean, this is fairly straightforward isn't it? Have a tank with nothing but tap water in it, top off with RO for 2 years and with the exception of the minerals which condensate at the water line as it lowers now and then, your water will remain mostly unchanged. However, if you fill a tank with tap water, and top off with tap water, over the course of 2 years wouldn't the tank begin to have ever increasing amounts of TDS in it? i.e. calcium and the other minerals dissolved in any natural water source? Wouldn't this contribute to a higher TDS?

If both of those are correct statements, and the plants themselves do not absorb the natural mineral buffers in your typical tap water (or at least not all of them) then topping off with RO water would keep your tank water consistent.
Which leaves one question/conclusion. If OPs tap water has a TDS of level X and his tank is now level B (B being noticably higher) then clearly there are only two options: 1) Something in the tank is leaching into the water column or 2) something outside the tank is being put in, which is eventually reaching the water column.

If 2 is the case, I would think that perhaps the fauna of the tank, or some minerals in the food supplied to the tank are slowly adding to the TDS.

Yes? No?

In either case, it looks from the post above that some of the things in OP's tap water such as calcium, are being taken up by the plants. Is it possible that all of the nutrients the plants can take from tap water have been depleted over time and haven't been replenished for some reason?
 

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Processes such as denitrification, osmotic regulation, respiration etc use minerals. As such these need replenishing
 

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Yes, something is adding to it. This may be a simplistic way to look at it but... If you are aren't REMOVING anything from the tank then everything that goes in food, plants, fish, wood etc. are adding to whats in the water column (RO water or, not) only so much is used by the plants. If you aren't removing anything then THAT is why TDS are rising. But, even though TDS are rising they are things that the plants AREN'T using(minerals that are in most tap water) this like Blacktetra said is the culprit.
 

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I set up a 30 Gallon Walstad style tank a year and a half ago and everything was going great!
If you are interested in the Walstad method and haven't acquired the book yet, I would say it's a must. And it shall be read and re-read...

Plants do use minerals (K, P, Ca, Mg, S, Fe and others). When I trim my plants, I remove minerals. Softwater plants will generally do well in both soft and hard water, but hardwater plants will not do well in soft water due to lack of minerals. D. Walstad elaborates on that aspect in her book.
 

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Discussion Starter · #16 ·
... Going back and re-reading your OP. Why are you intentionally trying to acidify/soften your water? Most aquatic plants come from at least slightly acidic waters but thrive, if not "do better" in water with moderate hardness(due to the availability of more trace elements in higher GH waters).
If you re referring to my use of bogwood, the water from the tap comes out at about pH 9. The fish I use are mostly softwater species (guoramis, apistogramma sp. bolivian ram, ember tetras, etc) hence the use of bogwood.

Do you have a copy of "The Ecology of the Planted Aquarium"? If not get a copy. If you do have a copy - re-read it. I've read mine several times and the more you read it the more you realize you missed or, refresh on things you have forgotten/didn't understand the first go around.
I do have a copy. I will do a re-read soon enough, though I am not sure that it will be more helpful than the information available through experience here on the forums. ;)


1. Though they are related these values are not the same. No, just topping off does not keep the values "the same." As I said, you are constantly INCREASING your TDS by NOT removing anything - only adding to your TDS.
This is the thing I am having difficulty understanding. Yes, I am not adding anything so shouldn't TDS be decreasing? After all, plants should be using up stuff in the water column, and since I am not adding anything TDS should be going down?


Using RO(pure H20) is not adding anything(Macros/mricros). With RO you have 0GH, and 0Kh(I do not know how pH is affected by RO - I don't use it nor have I ever. I'm not against it I've just never used it or read a lot on it). With a 0Kh you have nothing buffering your tank water ie. your water is constantly acidifying. The presence of carbonates in your water(KH) prevents/slows the constant acidification of aquatic environments. You may want to do some reading on what GH and Kh values reflect and how they affect aquariums as a refresher.
I agree with the point here that the low KH would mean lower buffer against the acidification of the water. However, my pH values are constant at 5.5

2. Yes, I use dechlorinator. Does RO remove chlorine/chloramine(like I said, I don't know)? Why are you letting it sit for a week?
RO does remove chlorine. When I use tap water, I let it sit for a week to let the chlorine dissipate. I don't use dechlorinator.

3. No, KH, GH levels are constant (possibly a few degrees of fluctuation at occasional water changes - not enough to notice a difference in my regents).. I don't test TDS but, yes, I'm sure they rise to an extent but should only reach a certain level before leveling out. However, in a healthy Walstad system there should be an equilibrium attained at which point everything should balance itself from uptake/input by plants(uptake) and fish/keeper(input) thus resulting in constant Gh, pH, KH.
If you only top with tap water, the only way Gh and Kh levels are constant is if you have an excellently balanced system where the plants use the extra minerals in the new tap water you add; i.e. perfect system. Congratz.

I'm sure I've left out some information and maybe added to confusion. Hopefully some one can explain better. In short. Start topping off with dechlorinated tap water you should see more growth soon. Also, try raising your KH and pH, remove the almond leaves. Or, simply add something to raise your KH(baking SODA, oyster shells), this will increase your pH at the saem time(different rate). Do a Google search for raising/maintaining KH in aquariums.
Will do, though I am wondering if adding mineral water would suffice as a short term solution.
 

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Discussion Starter · #17 ·
Perhaps this is a good chance for me to learn something here.

I was under the impression that if you topped off with RO water that the Gh and Kh would stay consistent, but that if you topped off with tap water you would be adding to the water column some things which plants won't absorb/eat/uptake and as a result, over long periods would see larger and larger amounts of minerals in the water, contributing to a very large TDS I would assume.

I mean, this is fairly straightforward isn't it? Have a tank with nothing but tap water in it, top off with RO for 2 years and with the exception of the minerals which condensate at the water line as it lowers now and then, your water will remain mostly unchanged. However, if you fill a tank with tap water, and top off with tap water, over the course of 2 years wouldn't the tank begin to have ever increasing amounts of TDS in it? i.e. calcium and the other minerals dissolved in any natural water source? Wouldn't this contribute to a higher TDS?
This was what I was trying to say exactly, hence my confusion at the reply from HDBenson.

If both of those are correct statements, and the plants themselves do not absorb the natural mineral buffers in your typical tap water (or at least not all of them) then topping off with RO water would keep your tank water consistent.
Which leaves one question/conclusion. If OPs tap water has a TDS of level X and his tank is now level B (B being noticably higher) then clearly there are only two options: 1) Something in the tank is leaching into the water column or 2) something outside the tank is being put in, which is eventually reaching the water column.

If 2 is the case, I would think that perhaps the fauna of the tank, or some minerals in the food supplied to the tank are slowly adding to the TDS.

Yes? No?

In either case, it looks from the post above that some of the things in OP's tap water such as calcium, are being taken up by the plants. Is it possible that all of the nutrients the plants can take from tap water have been depleted over time and haven't been replenished for some reason?
Perhaps there is something leeching minerals into the water... If that is the case, whatever is being leached into the water is 1. not lowering the pH 2. is not increasing the KH and 3. is not beneficial to plants (due to the stunted growth and holes in the leaves of the plants). Will have to find the culprit but have no idea how... There are 2 bridges as decoration made out of clay (baked, like clay vases)... Could they be the culprit?

Bump:
If you are interested in the Walstad method and haven't acquired the book yet, I would say it's a must. And it shall be read and re-read...

Plants do use minerals (K, P, Ca, Mg, S, Fe and others). When I trim my plants, I remove minerals. Softwater plants will generally do well in both soft and hard water, but hardwater plants will not do well in soft water due to lack of minerals. D. Walstad elaborates on that aspect in her book.
OK this would explain the Anubias leaves having holes in them, but not the tiger lotus, E. Azurea, Anacharis, subutula, amazon swords and other soft water plants.

Regarding the minerals, I do know that plants use minerals... I had thought that the dirt in the soil would provide at least the majority of these over time?
 
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