Chemical questions around phyto culture sanitization

[Goonter]

I’m about to try and culture my own phytoplankton and I have several questions, mostly about the sanitization and fertilizer.

If I am using 7.5% bleach to sterilize 1 gallon of water (I think I’ve read this needs to be 2.5 ppm), I need 0.14 mL of bleach?

How long should sanitization take? 30 minutes?

I purchased STS to neutralize the bleach. How much of this do I use? Also do I just mix the powder in or make a separate solution to add?


Any idea how long this takes to neutralize?

Would sodium ascorbate be a better option than STS for neutralization?

Is there any problem with adding the bleach to saltwater and f/2 fertilizer and then neutralizing it, or am I supposed to only do it to the RO prior to mixing the salt and fertilizer in?

If I am growing some diatoms that require silicate in the fertilizer, is there any problem with adding sodium silicate (water glass) to f/2 fertilizer?

Thanks!

 

[JimWelsh]

I’m about to try and culture my own phytoplankton and I have several questions, mostly about the sanitization and fertilizer.

If I am using 7.5% bleach to sterilize 1 gallon of water (I think I’ve read this needs to be 2.5 ppm), I need 0.14 mL of bleach?

How long should sanitization take? 30 minutes?

I purchased STS to neutralize the bleach. How much of this do I use? Also do I just mix the powder in or make a separate solution to add?


Any idea how long this takes to neutralize?

Would sodium ascorbate be a better option than STS for neutralization?

Is there any problem with adding the bleach to saltwater and f/2 fertilizer and then neutralizing it, or am I supposed to only do it to the RO prior to mixing the salt and fertilizer in?

If I am growing some diatoms that require silicate in the fertilizer, is there any problem with adding sodium silicate (water glass) to f/2 fertilizer?

Thanks!

Tons of good questions. I used to have the answers to most of them memorized, but that was many years ago. You might consider trying googling the phrase "humble fish" and asking over there.

To try to answer your questions as well as I can:

That 0.14 mL calculates out to be about right.

The longer the better for sterilization. Are you in a big rush?

You make a separate solution of thiosulfate, but I don't have specific concentrations at my fingertips. Sorry.

Neutralization happens quite quickly. But, to be safe, give it a few minutes. Again, are you in a big rush?

You should sterilize the ASW + F/2. Do you have any idea how much crap you're going to introduce with the salt and the F/2!?!?

Silicate tends to precipitate out, but, no, there is no problem with adding it, and you are correct that diatoms need it.

Best of luck with your cultures!

 

[Goonter]

Tons of good questions. I used to have the answers to most of them memorized, but that was many years ago. You might consider trying googling the phrase "humble fish" and asking over there.

To try to answer your questions as well as I can:

That 0.14 mL calculates out to be about right.

The longer the better for sterilization. Are you in a big rush?

You make a separate solution of thiosulfate, but I don't have specific concentrations at my fingertips. Sorry.

Neutralization happens quite quickly. But, to be safe, give it a few minutes. Again, are you in a big rush?

You should sterilize the ASW + F/2. Do you have any idea how much crap you're going to introduce with the salt and the F/2!?!?

Silicate tends to precipitate out, but, no, there is no problem with adding it, and you are correct that diatoms need it.

Best of luck with your cultures!

Thank you, that gives me a decent idea of the process.

 

[Goonter]

Thank you, that gives me a decent idea of the process.

Bump in case there are more insights. Thanks!

 

[Randy Holmes-Farley]

I'll just add that if you put silicate into the phyto culture, it may mostly grow diatomns.

 

[JimWelsh]

I'll just add that if you put silicate into the phyto culture, it may mostly grow diatomns.

If it's a diatom culture, like Chaetoceros, I would sure hope so! A pure starter of, say, Isochrysis, won't grow diatoms just because you added silicate.

 

[Goonter]

I'll just add that if you put silicate into the phyto culture, it may mostly grow diatomns.

That is the hope for chaetoceros.

@Randy Holmes-Farley I have three specific questions I am hoping you can help me answer:

1) the following is what I’ve found is the concentration for a stock solution then add it at 1 mL/1L. If I am having a 2.5 L total solution, how much water glass can I add directly to the culture (instead of a stock solution) to get this same concentration?

here is the water glass I have on hand:

2) how much STS is needed per gallon to reduce 2.5 ppm of bleach? Using this chemical, it sounds like I need to make a stock solution, but I’m not sure how to do that?


3) are there any long term negative impacts to the reef tank by dosing STS to the reef tank (as part of the phyto culture dosing)?

 

[JimWelsh]

This might help. Note that it's calculations are based upon 5% bleach, vs. your 7.5%. https://shellfish.ifas.ufl.edu/wp-content/uploads/Phytoplankton-Culture-for-Aquaculture-Feed.pdf

 

[Goonter]

This might help. Note that it's calculations are based upon 5% bleach, vs. your 7.5%. https://shellfish.ifas.ufl.edu/wp-content/uploads/Phytoplankton-Culture-for-Aquaculture-Feed.pdf

Thanks man, appreciate all your help with this so far— I saw this but I think it finally clicked that I can logic through it. This is saying 1-5 mL of 5% bleach to get it to 2.5 ppm chlorine. Then add 1 ml STS per 4 ml of the bleach. So 0.25 mL STS/1 mL of 5% bleach.

the problem is when I used a chlorine calculator. It tells me that 0.2 mL of bleach (5%) /gal is 2.5 ppm. Which is different from what this article is saying.

So if I use 7.5% bleach for 1 gallon to get 2.5 ppm is 0.13 mL of bleach. this means 0.2*0.05=0.1. 0.1/ 0.13mL =0.077 mL of STS per gallon. If my math is mathin’ haha.

 

[Randy Holmes-Farley]

If it's a diatom culture, like Chaetoceros, I would sure hope so! A pure starter of, say, Isochrysis, won't grow diatoms just because you added silicate.

I do not have any experience growing phyto, but getting contaminating diatoms into a culture not intended to be diatoms to allow them to grow does not seem particularly unexpected.