Possible BBA and a host of questions

hypnogogia

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JBL Ferropol 40ml at water change and 20ml mid week in addition to the NPK
Ok, so Ferropol is iron I think and then the NPK, so you are not adding any magnesium. Have a look at your water suppliers water report to see how much magnesium is in your tap water. If it’s low, you will need to add as a salt. Look for MgSO4 (Epsom salt). Be careful of looking for Epsom salts as some of the ones on places such as amazon have other additives for bath use. I use this https://www.aquariumplantfood.co.uk/fertilisers/magnesium-sulphate.html
 

Marcus_F

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Just checked Ferropol and yeah no magnesium, I thought it was a complete micro nutrient product.
 

dw1305

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jaypeecee

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Hi @Marcus_F
So fairly sure Diatoms is right, it’s on my gravel, some other plant leaves and I just wipe away but would be lovely to finally get rid.

Diatom growth is sometimes the result of excessive silicate in the water. I've just re-visited this subject as a result of the problem you are having. I dug into the chemistry of this a bit deeper than the last time someone was reporting diatom problems. It seems that silicon dioxide (e.g.sand) can slowly dissolve in water to form something called orthosilicic acid. This is where Wikipedia has some useful information:

https://en.wikipedia.org/wiki/Orthosilicic_acid

My guess is that this is a form of silicon dioxide that diatoms can use. As Wikipedia says "A unique feature of diatom anatomy is that they are surrounded by a cell wall made of silica (hydrated silicon dioxide), called a frustule". There is a test kit that can measure silicon dioxide (SiO2) as follows:

https://www.jbl.de/en/products/detail/8664/jbl-proaquatest-sio2-silicate

Or, you could save yourself yet another purchase by trying to get this information from your water company. I checked my water company's report for 2019 and - zilch! But, you could email your water company asking about the silica, silicon (dioxide) or (ortho) silicic acid.

Because this may be relevant, what is the pH of your tap and aquarium water?

JPC
 

Marcus_F

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Thanks all, @jaypeecee PH is 8.2. The diatoms have been around for a while now, some 6months I reckon without really being able to get to the bottom of it. I think the test kit would be a good thing albeit yet another purchase but worth it I think. I tried adding a filter (well looked for a filter media) to reduce silicates but couldn't find anything. I think maybe Diatoms don't like light either, so increase of light power could work.

I arrived home from fish shop today (first time in months) with 5 more shrimp (up to 7 now) and two dwarf catfish to help with the algae. I've no real issues with having algae, not like I need a 100% clean tank, just dont' want it taking over ther the tank or stopping plant growth.

@Geoffrey Rea I'll look at that, now I know more about fertiliser instead of having odd bottles all over, I'm going to look for one more complete options.
 

Marcus_F

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Nothing in my water report although it's quite a complicate read.

Can't see any value for Silicate. Does tell me their PH is an interesting read.

Hydrogen Ion (pH) pH value

PCV: 6.5-9.5
Min: 6.9
Mean: 7.2
Max: 7.9

When I test out the tap it reads as 7.6 I think but when oxygenated it raises to 8.2 which the tank reads also.

Found this on water supply guess it's Mg?

Manganese µgMn/l

PCV: 50
Min: <1.0
Mean: <1.0
Max: <1.0

Not sure what the PCV figure is in relation to the water supply, I'm guessing you should look at the Mean value for what comes out the tap?
 

Marcus_F

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Yeah no Mg relating to Magnesium. Think the other Mg values are for milligram or something not the chemical element.
 

dw1305

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Hi all,
It seems that silicon dioxide (e.g.sand) can slowly dissolve in water to form something called orthosilicic acid. This is where Wikipedia has some useful information:
I don't think it says that sand or diatom frustules etc are even minimally soluble at ambient temperatures or pressures. It says, for amorphous silica
.....This equates to a maximum solubility of about 2 mmol L−1 at ambient temperatures..........
but I think we would be dealing with crystalline silicon dioxide and that that is insoluble.

cheers Darrel
 

sparkyweasel

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I tried adding a filter (well looked for a filter media) to reduce silicates but couldn't find anything.
I don't think anything would reduce silicates to below the level that diatoms can utilise, it's in the parts-per-billion range.
While the test kit might tell you how much is in your water, it doesn't really help it you can't do anything about it.
And do you need to do anything about the silicate level? Probably not. Diatoms do need silicates, but to construe that silicates cause diatoms is just marketing.
 

jaypeecee

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Hi @sparkyweasel
And do you need to do anything about the silicate level? Probably not. Diatoms do need silicates, but to construe that silicates cause diatoms is just marketing.

Since diatoms need silicate, it follows that reducing the availability of silicate may reduce/eliminate the development of diatoms. Just like shrimp and calcium. Take away the latter and shrimp wouldn't live very long.

JPC
 

dw1305

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Hi all,
Since diatoms need silicate, it follows that reducing the availability of silicate may reduce/eliminate the development of diatoms.
That is correct, but only relevant if you can get the concentration below two micro-molar orthosilicic acid in solution, one you are below that level it will begin to limit diatom abundance.
Diatoms do need silicates, but to construe that silicates cause diatoms is just marketing.
Yes that is the one. It is back to the "fixed nitrogen" and "nitrogen gas" difference.

<"Crystalline silicon dioxide isn't soluble">, it doesn't matter how much sand etc you in the tank, it doesn't go into solution.

cheers Darrel
 

Marcus_F

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All very helpful info. All I can read is you get brown algae during cycling, well think 9months in my tank should be cycled and still see co start brown algae on substrate and leaves. I can rub it off with my thumb.
Is there a way to help reduce it?
 

Nick72

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All very helpful info. All I can read is you get brown algae during cycling, well think 9months in my tank should be cycled and still see co start brown algae on substrate and leaves. I can rub it off with my thumb.
Is there a way to help reduce it?

Two weeks ago I took 80% of my plants out of the tank and washed them by hand. The diatoms come off easily, but the plants suffered from the stress of removal.

Two weeks later and they are all covered in diatoms again.

A gravel vac will also help for a week or two, but it's no long term solution.

I'm still hoping mine will clear up with time, but you've waited 9 months already - so I really don't know.

Do you have any snails, sucker fish, etc..?
 

Marcus_F

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Do you have any snails, sucker fish, etc..?

I have 5 snails who do a great job on glass and stones, not so much the plants. I just got two dwarf catfish who only eat algae so hopefully they will help with leaves. I have 7 shrimp now too who like the wood and my heater.
 
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