# Diatoms (Brown Algae) in a coldwater planted tank



## Aeropars (1 Jun 2008)

Hi guys,

I thought i'd give my goldfish tank a bit of attention as its sits in the dining room gettin pretty neglected at the moment.

I know newly set up aquariums generally suffer from diatoms however this has been going on for over 2 years now. I thought it was something to do with the black sand i used form my LFS and was possibly causing silactes to leech into the water so i binned that and am currently operating bare bottomed with 2 bits of bogwood with some massive java ferns attached. I havent dosed this at all apart from water changes and even they are in frequent.

I though i'd try and get this stabilised as its really ugly and even my borneo suckerfish cant keep up with eating it all.

Does anyknow have any explanation for this and perhaps ways i can combat this once and for all? My tropical suffered the same thing for ages but i think its now about gone from there. Could dosing improve things for me? 

Thanks in advance.


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## ceg4048 (1 Jun 2008)

Hi Lee,
    I've never bought into the whole silicate explanation myself. My view is that fundamentally, this algae, like the rest are triggered by ammonia. Once they form, then yes, maybe they uptake silicates and other compounds, but that excess silicates cause them? I don't think so. Two years of diatom algae ought to put the kibosh on this theory.  

If you are neglecting the tank then stop neglecting it, do frequent water changes, think about flow and filter capacity and all the rest of the things that we talk about. Is the tank planted? If not there is no point in dosing anything. There are a few plants that don't mind cooler temperatures and that the goldfish may not eat so check in to putting some of these plants in there. Then dose it.

Cheers,


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## Aeropars (2 Jun 2008)

Hey Clive,

The tank is planted with 2 large Java ferns so they are really only slow growing.

I only have 3 goldfish in there, and 5 borneo suckerfish who do munch their way through the stuff. Filter has more than enough flow (cant remember off the top of my head exactly how much) but we're looking at around 700lph minimum and the tanks a 120l.

I have to say that this is the one algae that stumps me every time and is possibly the worst looking. Going bare bottom certainly helps with the clenliness of the tank but i have to admin i dont do frequent water changes on there.

A far as dosing goes, how do you think i should tackle it? I'm not sure if coldwater changes things at all as i guess java ferns grow slower in cold water. My lighting is 2 x T8's (19watt i beleive) that come with the Juwel Rio 120 but i've got a couple of new daylight bulbs on there now.

I'm also going to be putting a substrate in there so any suggestions for that would be apreciated.


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## ceg4048 (2 Jun 2008)

Hi Lee,
          The ferns are probably growing slow due to the lower lighting and lower nutrient levels as much as due to the low temperatures. If you check the substrate page on AE=> http://www.aquaessentials.co.uk/index.p ... 8u78nma5p3 you can choose from any of the options there depending on the kind of look you are after or you could go the sheaper route and just use an inert substrate like regular pea gravel or Aakdama. It depends on the look that you want. Now, the ferns don't care about your substrate choice because the rhizome is mounted above the substrate on rocks or wood but there are other rooted plants that can be used here and that would appreciate a nutritious substrate:
Rotala Rotundifolia, Sagittaria Subulata, any of the Vallisneria and even the very difficult carpet plant Samolus Valerandi. Any of the Egerias like E. densa also do well here as does some of the Bacopas like B. monnieri.

I checked zooplus and they have a "goldfish set" that includes some of these but they might need a little bit more light to do well: http://www.zooplus.co.uk/shop/fish/aqua ... ater/43327

If you decide you only want to grow ferns then you can get by with an inert substrate like sand or gravel but if any of the rooted ones above strike your fancy then I would spend the extra cash and get a nutritious substrate. Then you can also dose with TPN+ or with the dry powders as you wish, but you won't have to dose as manically as in the higher light tropical regime, perhaps once or twice a week. This should definitely resolve the brown algae issue.

Cheers,


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## Aeropars (27 Jun 2008)

Clive,

I've decided to go with the inert substrate and stick to my ferns.

What would you suggest I dose. I'm using James PPMD+PO4 in my main tank. Can I use this formula here as well but doing once a week for the stated 2ml per 40l of water?


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## ceg4048 (28 Jun 2008)

Yep, low light, non-CO2 and fern only? Just use the same stuff and dose weekly, enough to keep them ticking over. 

Cheers,


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