Algae revisited

Hrm,
I have almost exclusively diatoms(they aren't "brown algae"(Phaeophyta)....I read up...),ie Bacillariophyceae, on my glass and nowhere else......Strange eh?
These little bugger seems to have a cell wall of almost exclusively silica, SiO2. One of their biggest problems is finding enough silica.

They are found in environments rich in SiO2 and often prefer small amounts of light - better to turn the light on than off to get rid of these

The fun part when you think of it is that I find them mainly on glass. Glass is made of SiO2......

Are these buggers eating my glass and turning it into cell walls?? The cost of breaking the crystal structure of the glass must be to heavy, right? What means would they use?
Or do the glass actually give off enough silica to support big populations of these?

It might be that we simply have a lot of silica in our water and that it is just a coincidence that I find them on the glass....

Anyway, do you also find a lot of diatoms on your glass? They look like a fine layer of brownish algae, sometimes they accumulate in spots.

Hi Jesper,
If you are getting your water from a municiple supply then there is usually silicate added to the water to prevent the pipes from corroding. This coats the pipes and prevents it from any further degredation (but it causes huge diatom blooms).
I spent almost a year working in the R&D Labs for one of the major silicate and zeolite companies in the US. So I got to see lots of technical information.

Ed

Aha!
You sure are a never ending supply of very diverse information Ed!

So do you pros use something that precipitates it to avoid being run over by them or do you simply use "better" water?

The best thing for my tanks would be to take your advise and used distilled water or similar water(when making up for evaporation), problem being that it is kind of difficult to bring about 100 litres of water from the lab every week. The alternative would be to start distilling myself but that would be way way to expensive so I'll have to keep using the municipal supply.

Well that is one of the things that occurs as you get older, you aquire odds and ends of information....
If you had a salt system I would suggest bumping the pH up to about 8.5 as this makes the silicate unavailable to the diatoms but this is not practical in most fresh water systems.
You can buy RO systems that have an ion exchange system built into it that will remove the silicates but silicates are pretty difficult to remove from the water supply in general....
Ed

A large reef tank that I help maintain had algae problems and it too was put down to silicates, And that was through an RO unit, so some still did get through the membranes...

If using RO water (which you can buy reasonably cheaply from shops which specialise in marine fish) you have to mix it 50/50 with tap water as RO water has no buffering capabalities and no trace elements suitable for an animals needs, amphibians would suffer in pure RO water.

Once a tank is cycled and matured then the diatoms will naturally die off and be replaced by other less unsightly algaes...

you can also buy test kits for silicates if you wanted?

Hi Colin,
Did you have an RO unit made to remove silicates? I use them at work and there is an ion exchange unit after the RO membrane to "polish" the water after it passes through the membrane.
In established reef systems, diatoms usually do die out as they bind the free silicate into shells but if you have a high evaporation rate and add lots of water containing silicate to the system it will maintain the diatom bloom as will multiple water changes).
If the RO water is being used to replace water that has evaporated then the RO water does not need to be modified as there is no overall change in the total salt/buffering content of the tank.
Ed

I would just like to point out that I was never thinking about filling the tank with distilled water just replace evaporated water to keep the ionic strength down on Ed's suggestion.

I have started to do pretty hefty water changes each week now my plants started to not enjoy my previous tactics(no water changes...just refilling) after half a year or so.....
Newts didn't have any problems though.
Also as the plants basically stopped growing the algae started to take over.
I imagine the ionic strength was pretty high....

The diatoms I have sure doesn't go away by themselves - I imagine they should be quite a big problem for newt tanks since I assume most is run with low lighting(or maybe we just have high silicate content here).


(Message edited by jesper on April 11, 2004)

Hi Jesper,
I have a couple of systems at work that have had a continous growth of diatoms for about 7 years now.
I suspect your plants have wiped out a couple of the trace elements and the water changes will help get your plants going again..
Ed

Just a thought... i think that disus keepers have a product which they use to enrich RO water with beneficial chemicals... used in place where tap water nitrates are high... maybe worth checking a local shop?

Ed, the RO unit didnt have an ion exchange after the membranes, but over time the diatom went on their own accord... got replaced by macro algaes.

I use zeolite gravel substrate in my tanks and filtration-systems for over 2 years now: superb water-quality and no algae at all. expensive but longlasting great stuff.

Han.

Hi Han,
When I last checked, the zeolite used in the aquarium industry was one of the mordanites. These works by ion exchange and by trapping cations and ammonia within the lattice work. The pores in the lattice work are the proper size to mechanically trap and with a slight negative charge bind a range of the cations. Typically the lattices are loaded with sodium. If I remember correctly the first choice for ion exchange is for iron, followed by calcium the magnesium with ammonia being much further down the list. The concern with this is that if there are insufficent water changes the sodium content will slowly increase the salinity of the systems and eventually cause problems.

Ed

Hi Ed

You might be right but i never noticed any problem
with my animals (anurans)living in tanks with zeolite-substrate. Using heavy-duty canister Eheim
filters, i change water only once a year. a raining-system fills up the evaporated part every day to keep up the water-level.
the use of live plants however is out of the question: not enough food in the water.
i'm not very much into chemistry, but with your expertise, have a look at the english articles at www.zeolife.nl

Han.

Hi Han,
Unfortunately I cannot read the language on that site. I worked in the research industry with Zeolites for a little over a year which is where my information comes from but this was over 15 years ago so I might have lost some of the details.
The use of zeolite on a planted aquarium would limit the growth of plants as one of the first elements removed from the water is iron with is necessary for plant growth.
Do you use RO or distilled water for your top off water?
Ed

Hi Ed

I use tap-water for top off water. Water-quality in the part of Holland where i live is ok (ph 7.5).
There are several english pdf.files at www.zeolife.nl ("artikelen") dealing with the use of clinoptilotite (a zeolite)as ammonia absorber in fishbreeding/transportation.

Han