# [Wet Thumb Forum]-SiO2 out of controll



## ROSS (Oct 8, 2003)

hi to all, i may be posting in the wrong topic but it sounded right when i read the science part!!

i have used with much disapointment a latterite/quartz/vocanit substrate, my decor includes wood and pure slate and the bio is 80% planted with an arcadia 3 pendant!

thats the background here's the problem-
I have an excess silica reading of nearly 2ppm after using RO water and within 7 days of it being in the aquarium, i have tested the quartz,latterite,volcanit to find the vol/lat seem to be leaching small amounts of SiO2 into the water columb (i'm no expert in any way and have used pure RO and test tubes with small deposits of each left for seven days then tested with red sea test kit).

RO starting point was jut under 0.25 ppm but after 7 days was showing results closer to 1ppm!

this bio has been running for about 6 months with what started out as lavish plant growth but has now degenerated to the perfect algea farm, although plant growth does not seem to be affected unsightly algea seems to be taking over the asthetics of the aquarium.

i suppose what i'm asking is would anyone have any ideas on how to remove silica without either stripping the aquarium or removing the substrate, are there any products known to remove or reduce or will i just be banging my head of the glass in a month or so?

sorry to babble on, many thanks for listening.
ROSS.


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## ROSS (Oct 8, 2003)

hi to all, i may be posting in the wrong topic but it sounded right when i read the science part!!

i have used with much disapointment a latterite/quartz/vocanit substrate, my decor includes wood and pure slate and the bio is 80% planted with an arcadia 3 pendant!

thats the background here's the problem-
I have an excess silica reading of nearly 2ppm after using RO water and within 7 days of it being in the aquarium, i have tested the quartz,latterite,volcanit to find the vol/lat seem to be leaching small amounts of SiO2 into the water columb (i'm no expert in any way and have used pure RO and test tubes with small deposits of each left for seven days then tested with red sea test kit).

RO starting point was jut under 0.25 ppm but after 7 days was showing results closer to 1ppm!

this bio has been running for about 6 months with what started out as lavish plant growth but has now degenerated to the perfect algea farm, although plant growth does not seem to be affected unsightly algea seems to be taking over the asthetics of the aquarium.

i suppose what i'm asking is would anyone have any ideas on how to remove silica without either stripping the aquarium or removing the substrate, are there any products known to remove or reduce or will i just be banging my head of the glass in a month or so?

sorry to babble on, many thanks for listening.
ROSS.


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## Roger Miller (Jun 19, 2004)

You don't need to remove silica. Certainly you don't need to remove it to the levels that you're talking about. Normal water supplies contain around 10 ppm. My water supply is unusual in that it contains about 50 ppm.

There are a lot of reasons why algae can cause problems in freshwater tanks, but silica is generally not one of them. You need to look to different causes.


Roger Miller


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## ROSS (Oct 8, 2003)

thanks for your wisdom, i'm left feeling quite red faced!

I will read more, although I have successfully cleared the majority of the growth i'm just left with the most persistant beard types. I was trying to starve the algea without the use of bleach dips or intro of copper. You are now fully aware of my lack of understanding when it comes to this subject, but my persistance is matched by that of the algea, and now with the inroduction of fish to the aquarium I feel some what limited as to what I can do!

I sugested in my previous post the Arcadia pendant, which gives extremly high output with the use of halide lighting to nearly 5wpg. Would a different lighting cycle be of help or should I just stick with nutrient balance and let patience be my guide. Any sugestions in lay-mans terms would be welcomed along with a deeper understanding of why you ruled out silica so quickly?


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## Roger Miller (Jun 19, 2004)

Last things first. I ruled out silica quickly because silica is used only by diatoms; diatoms are an occasional problem but usually fade away on their own and/or are easily controlled. No other algae and probably no aquatic plant is dependent on silica.

Silica can control diatom blooms in seawater but that is not true in fresh water. This is one of those details where advice from marine aquarium keepers doesn't transfer well to planted tanks.

High light certainly can contribute to problems -- especially if you're relatively new at planted tanks. You didn't say what your light cycle is so it's hard to recommend a change. Usually there is little to be gained by using light cycles other than 10-14 hours on and 14-10 hours off.

You haven't given us much to go on as far as further advice goes. If you can tell us more about your water supply, fertilizers, CO2 supply (if any), size of your tank and number and kind of plants you're growing then we can help more.

One thing I can say now is that "starving" algae in a planted tank won't work unless you also provide a fertile substrate for the plants. Algae are much more well-adapted to growing at low nutrient levels then are plants. By starving the algae you also starve your plants.

Analogies to flower or vegetable gardens don't usually work very well, but I'll try this one anyway. Witholding fertilizers from a garden does next to nothing for controlling weeds and usually hurts your flowers and crops more than it hurts the weeds. Weeds tend to dominate if the soil isn't very fertile. In a planted tank (our gardens) our plants are the crops and the algae are the weeds.


Roger Miller


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## ROSS (Oct 8, 2003)

thank for the reply and setting me straight when it comes to silica and algae! i'm sorry it takes me some time to reply but things are a little busy at present, although I appreciate your help/advice..

my light cycle is twelve hours 6 of these hours are peek light cycle with both halides and tubes running the rest is tube only.

the substrate consists of volcanite which is volcanic rock frags and latterite under a deponit mix wrongly or rightly used in the hope of suppling FE and creating a good home for bacteria to colonise, the deponit mix is obvious!

ferts i use for the water Coulomb include leaf zone, chempak, aquaponics NO7, i must admit i don't know whats in the NO7 because it don't say, but i have good plant growth as well as the algae!!

I do use CO2 with the help of an needle valve! what do you think to using a solenoid at night?

what test results would you like to know STD tests are all fine NO3/NO2/pH/KH/GH/PO4/NH3.
I don't think i'm using the CO2 calc right as i seem to get strange readings.

Let me know what you would like to hear from me and i will post what ever is needed!


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## Roger Miller (Jun 19, 2004)

Ross,

Light at 5 wpg is definitely going to cause problems, even if it is at that level for only 6 hours/day. 

To get continued healthy growth out of your plants you need to provide them with nutrients -- including the nutrients that normally come in your tap water. Unless you provide your plants with a fertile substrate you will never be able to starve the algae in your tank without first starving your plants.

It sounds to me like you need to back off on your lighting. How much light do you have with the pendant off?

You also need to give your plants water that is richer than RO water. Usually tap water is your best choice. In some cases a mix of RO and tap water is OK. Once you have those changes you will also need to make sure that your plants are fully supplied with nutrients.

I'm not sure what you mean when you say that the standard tests are all "fine." To me that usually means that NO3 > 5 ppm, NO2 is 0, KH and GH are over 3 or 4 degrees, pH is near neutral, PO4 is measurable and NH3 is not. Is that what you mean?

What plants are you growing?


Roger Miller


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## ROSS (Oct 8, 2003)

OK, without the pendant on there is only room light which is low to say the least, i only have the front of the tank showing in the living room the rest is in a cupboard! if i only use the tubes there is 60w total over 240 ltr's of water, what would you suggest?

give or take a little my readings are as you posted NO3 being a little higher but not out of control, and KH sitting steady at 6, pH 6.8 all other tests are as you suggest!

when it comes to the plants there's nothing to special! i have some glos, java, anubias,red sword, some very large crypts and some small parva and willisii, a whole load of vallis, reineckii, and a huge echinodorus rubin in the centre. As i say they grow well but so does the algae.

i know my susbstrate is pretty rich due to using the deponit mix by dennerle and the latterite! but i must admit i'm not to conversant with the actual micro/macro side of plant feeding. Although i have just purchased what i'm led to believe is a good book that i'm hoping will help!?...

i dont wish to be a burden, but i'm pretty green to it all! (excuse the pun)


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## Roger Miller (Jun 19, 2004)

First, with a KH of 6 degrees and a pH of 6.8 your CO2 concentration should be about 24 ppm. That's fine.

Given a choice between 1 watt per gallon and 5 watts per gallon your plants are probably better off at 5 watts per gallon. In the long run you might want to see about using lower wattage halides or adding more flourescents. You can get things working under high light, but it is more difficult.

Of the plants you list, only the glos (I assume you mean glossostigma elatinoides) is a high light plant and even that should be fine with less than 5 wpg. The A. reineckii probably will look good with 3 watts/gallon of good lighting but probably doesn't need more. The rest of the plants might actually do better with lower light.

One thing you can do right away to help fend off the algae is to add a lot of fast-growing plants. Hygrophilla polysperma, Rotala indica and Egeria densa are good examples. If your valisneria is a tall variety then you can also let it spread out and shade the tank.

I'm not familiar with most of the fertilizers you're using. You need to make sure that you are giving the plants balanced nutrients. That might be difficult to do with mix-and-match products from different manufacturers.

Last, keep manually removing the algae in the tank. If you recently added fish then you might see a change in the amount of kind of algae that are growing. If your fish population doesn't currently include some good algae eaters then you might consider adding a few.


Roger Miller


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## ROSS (Oct 8, 2003)

Again thanks for the reply.

while were on the subject of light, do you know how high from the tank the lights would have to be to lower the intensity to perhaps 3 watts per gallon!

75watt halides x2 presently 15" from the water surface, the aquarium is 15 deep to the top of the substrate, and 18" deep in total. Hope that info helps and if possible could you show me how you calculate the answer?

I will take your advice and try to add some faster growing species but i have run out of space unless i change the scape!

I have added some Otto's and have 15 shrimp fully grown.

the vallis is long growing but the new growth seems to be growing thinner in width! any clues?

my learning curve is huge at present, this "ecology of the planted aquarium" was said to be an informative yet easy read? I'm obviously not as inteligent as i presumed, a more basic understanding of nutrients both macro and micro will have to be read, i must also admit it sounds like my setup is a little to techno for what i'm reading. ?have i realy embarked on the hardest route to the beutiful planted aquarium?

its nice to know i got something right "CO2 concentration"


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## Roger Miller (Jun 19, 2004)

> quote:
> 
> while were on the subject of light, do you know how high from the tank the lights would have to be to lower the intensity to perhaps 3 watts per gallon!


That's a real good question, and one I can't help with. Maybe the people on the hardware forum could help.



> quote:
> 
> my learning curve is huge at present, this "ecology of the planted aquarium" was said to be an informative yet easy read? I'm obviously not as inteligent as i presumed, a more basic understanding of nutrients both macro and micro will have to be read, i must also admit it sounds like my setup is a little to techno for what i'm reading. ?have i realy embarked on the hardest route to the beutiful planted aquarium?


Great book, well written and loaded with information. It is definitely a technical book and like anything with a big technical content, reading it requires a commitment. I wouldn't call it an easy read.

Diana's approach is definitely not as technical as the course you set out on. Her methods also produces a somewhat different result. Depending on just what it is you want out of your tank and how much effort you want to put into it you may very well have taken the most difficult path. You're really the only one who can answer the question.

You might get a better sense for what you want to do by visiting at the "El Natural" forum (which Diana Walstad moderates) and talking to people who use her methods about whether you can get what you want with her methods or whether you need a more high-tech approach.

Roger Miller


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## Turin Turambar (Mar 1, 2003)

Sorry to interrupt, but after I added only one liter of water (in 60l aquarium) that had 13mg/l of SiO2, I had some serious diatoms problem that cured after 2 regular water changes. Strange?


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## Roger Miller (Jun 19, 2004)

Probably not related at all to the silica. If there was no SiO2 in the tank water to start with then one liter of water with 13 ppm SiO2 in a 60L tank increases the SiO2 in the tank by 0.2 ppm. SiO2 is not a trace constituent. 0.2 ppm is insignificant.


Roger Miller


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## Turin Turambar (Mar 1, 2003)

Yes, that is strange indeed. But unfortunately, I don't know the amount of silica in my tap water, so maybe that 1l triggered the diatom-bloom? Or that was just some weird coincidence.


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## Josh Simonson (Feb 4, 2004)

I agree that most of your plants are slow growing, lower light plants. This is probably the largest single cause of your algae problem. You should add rotalas, ammania, didiplis, cabomba ect. Also some floaters like riccia to provide shade to discourage algae. Riccia is fairly valuable stuff, so when it gets too big you can sell some off. With that much light you can prolly offset your power costs with riccia sales.


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## ROSS (Oct 8, 2003)

Hi, back again.

I thought it was tmie for an update, after using mt own RO unit i have noticed a drop in the amount of nwew algea growing, although there doesnt seem to be much change in the amount that was aready present, but one step at a time will do, I should also mention i have stopped adding iron as i think the latterite content in the substrate is to rich.

after reading your comments Roger "you might get a better sense" and the book, I feel it may have been easier! but I feel commited to rectifying the problems rather than stripping it back down now i'v spent the money.

I will post the question on the hardware site and take the advice!
but before I do, as an average what would you recomend to be the ideal WPG?

Thanks

Josh, Cheers for the comment, I only have a limited amount of space left for new plants what would be the best 2 to introduce considering what you have read from my previous comments?


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