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Aquarium sand and diatoms...

Wolf6

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I was going to suggest Oto's - they do require specific care, but they can clean a tank of diatoms in matter of days.
They clean my plants, rocks, wood and windows, but I dont ever see them on the sand other then briefly lying on it. Do yours clean your sand too? And if so, how did you train them :)
 

dw1305

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Hi all,
In the tank where I have had a Ramshorn Snail problem, there are also no fish or any other livestock.
They are doing well because they are eating the algae? If you really want to reduce their number, a slice of cucumber should collect quite few.

cheers Darrel
 

dw1305

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Hi all,
Do yours clean your sand too?
Malaysian Trumpet Snails work for this, I don't if that is because they continually rebury the top layers of sand? or whether they actually eat the algae?

cheers Darrel
 

Wookii

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Maybe I need a bag of silicatex or similar in the filter for a while

That's probably a slippery slope, and from what I have been advised by @dw1305 in the past, you will never be able to get the levels of silicates low enough to affect the diatoms - they can flourish on microscopic amounts.

They do appear to be very easily outcompeted by other organisms though, particularly other algae and plants, and possibly bacteria (?) which is perhaps why they're typically seen more in an immature tank.

Rather than silicate removers, your focus needs to be on whatever else in amiss with your set-up as Clive suggests. Something else is giving the diatoms an unnecessary advantage, or rather preventing the other higher organisms from establishing their dominance , if it is still persisting in your tank for 12 months.
 

Wookii

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They clean my plants, rocks, wood and windows, but I dont ever see them on the sand other then briefly lying on it. Do yours clean your sand too? And if so, how did you train them :)

Mine happily feed off the sand, though I've not had any diatoms on it, so I haven't directly seen them eat those off it. I'm more interested on how you've trained yours to clean your windows - that would save me a fortune on a window cleaner :p
 
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John q

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Once the silica concentration declines, other types of phytoplankton that do not need silicon typically replace diatoms as the predominant form of planktonic algae".

Just to throw a another spanner in the works and may be totally unrelated but if I reduce my light intensity I tend to get diatoms, if I increase it the diatoms disappear and gets replaced by algae. Trying to find that sweet spot in the middle is proving rather elusive atm.
 

dw1305

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Hi all,
you will never be able to get the levels of silicates low enough to affect the diatoms - they can flourish on microscopic amounts.
That is my understanding, because they are almost universal anywhere there is liquid water including damp moss, wet soil etc. you can tell that silicon limitation isn't really an issue for them.

<"SilicatEx" is interesting">, because it may reduce diatom growth, but not by reducing the amount of silicon. It also removes phosphates (PO4---) and phosphorus is one of the major plant nutrients.
But, that being the case, what then causes growth of diatoms?
They have the same requirement for nutrient as all the other photosynthetic organisms, but with the addition of silica (Si).
I thought I should re-visit this and found the following:

From the above link, I have extracted this:

"Studies of temperate-zone lakes have shown that diatoms often bloom in the spring, but this phenomenon leads to reduced silica concentration. Once the silica concentration declines, other types of phytoplankton that do not need silicon typically replace diatoms as the predominant form of planktonic algae".
I don't think any-one is saying that diatoms don't require silicon (Si), but I'm not sure that you can say that there is a correlation between silicon concentration and diatom growth in our tanks, particularly if you have higher plants (this is an aquaculture paper where the only plants are phytoplankton). Later on in the same publication it says:
........... and it is not known how low the silica concentration must fall before diatom growth is negatively affected..........It would be desirable to know the relationship between silica concentration and diatom growth, but this topic has not been investigated in aquaculture ponds. Lack of information about the relationships between silicate fertilization rates and silica concentrations in water, and how fast silica disappears from water also complicates efforts to encourage diatom growth..........
I always have snails in my tanks and I very rarely have any apparent diatoms (there will be diatoms present, because diatoms are pretty much universal in liquid water).

I'm willing to speculate that every fish keeper has diatoms in their tanks, unless they keep their tanks in total darkness.

cheers Darrel
 
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jaypeecee

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They lay eggs....but don't see young snails!
Hi @GHNelson

That's interesting. What's your secret? Do you have any water parameters that may explain this? I know that some critters' eggs only hatch under certain conditions. GH, KH, and temperature immediately spring to mind.

JPC
 

jaypeecee

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I don't think any-one is saying that diatoms don't require silicon (Si),
Hi @dw1305

Only @ceg4048 can give a definitive answer to this, I guess. Because it was his statement below that I was addressing. Have I misunderstood what he was saying here?

"neither sand nor silicates in the water column have anything to do with diatomic algae"

If it's me that's got the wrong end of the stick, then fair enough. But, as sand/silicates are SiO2 and particularly if an aquarist is using tap water, then surely diatoms will utilize the silicic acid? In which case, sand/silicates in the water column will have a bearing on the growth of diatoms.

JPC
 
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jaypeecee

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Just to throw a another spanner in the works and may be totally unrelated but if I reduce my light intensity I tend to get diatoms, if I increase it the diatoms disappear and gets replaced by algae. Trying to find that sweet spot in the middle is proving rather elusive atm.
Hi @John q

That's aquatics for ya!

JPC
 

GHNelson

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Hi @GHNelson

That's interesting. What's your secret? Do you have any water parameters that may explain this? I know that some critters' eggs only hatch under certain conditions. GH, KH, and temperature immediately spring to mind.

JPC
I have very high TDS out the tap 355!
Obviously this can go a lot higher if I dose ferts and I neglect the water changes.
 

ceg4048

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Hi @dw1305

Only @ceg4048 can give a definitive answer to this, I guess. Because it was his statement below that I was addressing. Have I misunderstood what he was saying here?

"neither sand nor silicates in the water column have anything to do with diatomic algae"

If it's me that's got the wrong end of the stick, then fair enough. But, as sand/silicates are SiO2 and particularly if an aquarist is using tap water, then surely diatoms will utilize the silicic acid? In which case, sand/silicates in the water column will have a bearing on the growth of diatoms.

JPC
Yes, perhaps you misunderstood. As Darrel mentions, algae consume all the same types nutrients that are present but there is no correlation between the nutrient level present and the rise of the algae. Just because silicates are present this does not automatically mean that a diatomic algal bloom is present. Algae require PO4 but PO4 does not trigger algal blooms. Similarly BGA require Nitrogen, but we can cure a BGA bloom by increasing the concentration level of NO3 in the tank.

As usual, it's very easy to take the results of studies out of context and to automatically ascribe the conclusions of cause and effect in those studies to our tanks. It's vital to understand what data we can use and what we can ignore. Algae behave differently depending on the environment, so for example in marine tanks, PO4 can trigger algae but in freshwater tanks this does not happen. The study you reference discusses the effects in temperate lakes and in seawater, neither of which are the same as a freshwater aquarium.

We need to understand that algae require only microscopic amounts of nutrients, so they really do not care how much nutrients are in the water. The main culprits are excessive lighting and chemical instability in the tank. Every one of our tanks has BGA, hair, BBA, diatoms, GSA, and all the rest of the known algal types sitting in the tank waiting for conditions to be be favorable for them.
Conditions favorable for algae are usually conditions unfavorable for plants. There is a relationship between plants and algae in the tank as well as in natural (or manmade) bodies of water, but those relationships are very different from body to body.

We can never eradicate algal spores from the tank, however we can practice good plant husbandry and in this way minimize the frequency and severity of their blooms. Algal blooms therefore cannot be resolved by limiting this nutrient or that nutrient and it is therefore unwise and ineffective to pursue the policy of nutrient eradication because doing so will usually lead to eradication of the very plants we hope to grow.

Cheers,
 

dw1305

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Hi all,
But, as sand/silicates are SiO2 and particularly if an aquarist is using tap water, then surely diatoms will utilize the silicic acid? In which case, sand/silicates in the water column will have a bearing on the growth of diatoms.
I understand what you are saying, but I still think we are in "apples and pears" territory.

Sand, glass, quartz, Diatom frustules and moler clay are all made of <"SiO2">, but none of them are soluble in the tank. The <"Baltic Shield rocks">, <"Lewisian gneiss"> or <"Gunflint chert"> are largely made of quartz and they are billions of years (10^9) old. If they had any solubility what so ever, at standard temperatures and pressures even the minutest amount, they would have dissolved aeons ago.

At high temperatures and pressures you can get silicon in solution (it is how you get bands of quartz in rocks etc.) and that is the silicon that ends up as traces of orthosilicic acid in rivers, streams, aquifers, tap water, the sea etc.

Diatoms extract orthosilicic acid from water to build their frustules, and they are incredibly efficient at it, we know this because nearly all liquid water contains diatoms. If we removed all of the orthosilicic acid from our water we would stop diatom growth, but it would literally have to be all of it.

The diatoms can't re-solubilise the silicon from their frustule, because it is quartz (SiO2) and that frustule will remain as <"insoluble quartz for all of eternity"> at normal temperatures and pressures.
...... Moler and diatomite consists of fossilised remains of a special type of hard-shelled algae, which gives the material its unique organic structure. Diatomite in general is over 30 million years old – the Danish Moler was formed more than 50 million years ago .....

cheers Darrel
 

jaypeecee

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Hi @dw1305

Thanks for your reply.

It seems as if the crux of this is that:

[1] Sand, quartz, silica and all forms of SiO2 in the tank itself are not going to encourage growth of diatoms due to lack of solubility

[2] Silicic acid in tap water may encourage and support the growth of diatoms. This assumes that additional silicic acid will be added at water changes.

JPC
 

jaypeecee

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Hi @ceg4048

I am a (retired) physicist and you are a plant biologist. Therefore, you are the teacher and I'm the pupil. So, my objective is to better understand the points you are making. Taking some of these points, let's start with the following:

Algae require PO4 but PO4 does not trigger algal blooms. Similarly BGA require Nitrogen, but we can cure a BGA bloom by increasing the concentration level of NO3 in the tank.

What, in your experience 'triggers' algae blooms? This implies to me that a number of conditions, when simultaneously present, will flick a switch and algae starts growing. It's what might be called a binary switch. What I'm hearing is that it's not a gradual process. Now, let's turn to Cyanobacteria/BGA. I've run several experiments in one of my tanks with cyanobacteria. I identified the cyano as Oscillatoria. Why does increasing NO3 cure a BGA bloom?

Let's leave it at that for the moment but I may have other questions for you.

JPC
 

dw1305

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Hi all,
Silicic acid in tap water may encourage and support the growth of diatoms.
It will definitely support the growth of diatoms, encourage is more open to question. My guess would be that it doesn't, purely because of the efficiency of diatoms in extracting silicon from any water source, so "some" is always going to be "enough".

While silicon (Si) isn't usually quoted as an essential plant nutrient, some plants extract silica (presumably also from orthosilicic acid) and use it for both stem strengthening and <"as a deterrent to grazing">. The most common examples are the phytoliths in grasses (think of Bamboo) and in Horsetails (Equisetum spp.).

A heavily silicified water plant is Hornwort - Ceratophyllum demersum, which has been <"reported to reduce diatom growth">, although allegedly via allelopathy rather than direct competition for silica.

cheers Darrel
 

jaypeecee

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While silicon (Si) isn't usually quoted as an essential plant nutrient, some plants extract silica (presumably also from orthosilicic acid) and use it for both stem strengthening and <"as a deterrent to grazing">.

Hi Darrel (@dw1305)

Interestingly, neither silicon nor silicates nor diatoms get a mention in the index of Diana Walstad's book, Ecology of the Planted Aquarium. Nor The 2Hr Aquarist. So, it's obviously not considered important to the growth of aquarium plants. At least, by some. But, take a look at the following:

https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.12614

JPC
 

dw1305

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Hi all,
neither silicon nor silicates nor diatoms get a mention in the index of Diana Walstad's book, Ecology of the Planted Aquarium. Nor The 2Hr Aquarist.
My guess is that in heavily planted tanks you don't really get obvious diatom blooms, certainly not after the initial start up phase.
Thanks for that, that looks an interesting paper.

cheers Darrel
 

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