Theory: Would Decreasing Water Chage Volume Cause Diatom Bloom

[RussC]

I have a 100 gallon volume setup. I use Red Sea Pro salt. When mixed, its about 11.4 ALK and 450 ish Calcium. My system wasn't running at those numbers, so every two weeks when I did a water change it would sway my numbers. I like it consistent. In an effort to stabilize water parameters, I have reduced from a 20 gallon water change to a 10 gallon water change. It just so happened at the same time, I bumped up my lights 3%. Now I've got a mean brown diatom bloom on my substrate. Could this be because I'm removing less nutrients with smaller water changes (in addition to more light)?


I know light is playing a factor because I can see the difference in growth of the algae (or lack thereof) under my big leather. My phosphates are measuring zero. But I know there are nutrients in that tank for no other reason than I feed frozen food every other day. But I've done that for a year now. So inquiring minds want to know. What are your thoughts, RCentral?

 

[mcgyvr]

Possible.. Sure..

"Assume"


You say nutrients like its always a bad thing..

 

[RussC]

I agree. Nutrients does not equal bad. Here's an extra tid bit. I recently removed cyano with ChemiClean. Absolutely excellent results. Substrate looked awesome. Then wham, diatom bloom. So I'm guessing the diatoms were competing with the cyano. When I removed the cyano, diatoms took over.

Its just ugly. I don' t like ugly.

 

[Tripod1404]

Diatoms numbers are mostly limited by silica. You should check you RODI water.

 

[Cliving1]

Diatoms numbers are mostly limited by silica. You should check you RODI water.

That's what I was thinking. I thought diatoms had to feed off of them to survive

 

[homer1475]

Any and every time I've had a diatom outbreak(except in a new tank), just increasing the flow in that area eliminates them.

 

[sfdan]

I actually dose Silica in my tank because I like diatoms, they are great food for herbivores and all your pods. And they can outcompete things that are far worse. So first I wouldn't go crazy changing things with your tank because of some diatoms, because looks aside, they are a perfectly good addition to your ecosystem.

But as people have said, they need Silica to grow. No silica, no diatoms. It is possible you had silica in your tank but something was preventing the diatoms from growing, then now with cyano gone they've taken over. But unless Silica is being replenished, they'll use it all up, get eaten, and then will slowly fade away. So if you are using RO/DI water, just be patient and they'll probably all be gone in a week or two without having to do anything. If you are using tap water, it is probably high in silicates. Either switch to RO/DI water or start to like diatoms.

 

[mcgyvr]

Substrate looked awesome..

And did you stir up said substrate when attacking this cyano problem and don't normally stir up the sand?
If so there is likely your answer...

I think we have had this talk about patience before...

Unlike most women in Mississippi "ugly" is only temporary and the diatoms will pass :lmao:... Just kidding women of Mississippi..

 

[RussC]

No, didn't mess with the substrate during the cyano problem. But I do have several critters that mess with it. You saying they could be a suspect for stirring up the "food" this algae is eating?

 

[RussC]

Diatoms numbers are mostly limited by silica. You should check you RODI water.

I've got the latest and greatest when it comes to my RODI system. Its less than 6 months old. So I'm betting the source for these diatoms has got to be in the tank already or I'm adding it through feeding. What are some silica sources?

I have a few new critters that move sand. They could also be stirring up some things in my substrate. What about bio load from my critters. Fish poo, for example?

I had one of these outbreaks early on in my tank before things settled in. Growing pains. I just bumped up the lighting and increased the length of time it was on and the diatoms just eventually ate up whatever it was they were eating and vanished. I starved them to death, basically. Worked like a charm.

I'm betting that will happen here, too. I do enjoy working the problem, though, understanding the why behind the what in this hobby. Pretty interesting stuff.

 

[Uncle99]

I've got the latest and greatest when it comes to my RODI system. Its less than 6 months old

...and TDS is 0 right....I gave seen after breakin "brand new" RODI systems which produced terrible water due to manufacture flaws and transport damage.

I always check each batch of RODI for TDS before putting all the good stuff back and so I know when my membrane needs change.

I am sure you do, just want to make sure cause this too is a likely cause.

 

[RussC]

Yep, TDS is zero. I check each batch.