Water change caused cyano bloom. What filter needs changing?

[Tired]

I did a water change a few days ago, and went from a small amount of cyano (high nutrients) to a large amount. The darn stuff's everywhere, overnight from the water change. I'm assuming this means something in my RO/DI unit needs to be changed or flushed or something along those lines. How do I tell what part is the problem and what to do with it? I'd like to suck a bunch of this cyano out, but I'm a little reluctant to do that when I'll just have to replace the removed water with more water that cyano apparently loves.

[paulsz]

1 hour ago, Tired said:

How do I tell what part is the problem and what to do with it?

If you want, you can check the TDS of your water. Then remove the DI cartridge and make some more water. Then use a TDS meters to check the new water. This would tell you if it's your RO membrane or DI resin that needs replacing. As for the prefilter or the chlorine/chloramine filter: if prefilter looks dirty (becoming brown), you can replace it. If you have chlorine test strips, test the chlorine from the "waste" water. If there's chlorine/chloramine, you'll have to replace that filter (i think it's called carbon filter).

 

As for the cyano bloom, I have little expereince with it so i can't tell you for sure that it's your water... I'll let someone else answer that. 

 

 

[Tired]

How would I tell from that which needs replacing? Is it just that if the DI cartridge doesn't seem to do much to the TDS, that's what needs to be replaced? 

 

I've read that using tap water can cause algae blooms, especially cyano. I did a water change and immediately had a big cyano bloom, so I assume the water was responsible. 

[Clown79]

For most city water sediment, carbon filter should be changed every 6 mnths. I change mine every 5 months. 

 

If sediment filter is brown- it needs changing

 

Di needs changing when it changes colour(i prefer using di that changes colour when its  exhausted) or when tds hits 1-2ppm

[Tired]

Alright, thanks. I'll swap those out.

 

The DI filter isn't yet exhausted, it's got an inch or so left, but I think I'm about to exhaust it. I'm going to filter a whole bunch of water to keep for my plants. I have some fussy plants (Nepenthes pitcher plants, mostly) that don't like tap water, but they don't mind water with a few TDS worth of stuff in it. May as well use up what's left of the filter capacity storing up water for them. 

[natedg200202]

do you have a TDS meter?  I'd start with testing the water coming out of the RODI system to be sure. 

Don't trust the color of the DI resin alone.  It can wear a bit over time and 'channels' can form through the media.  Water takes the path of least resistance through these channels and bypasses the resin (thus, TDS creeps above zero). 

[jarviz]

On 12/17/2020 at 4:42 PM, Tired said:

How would I tell from that which needs replacing? Is it just that if the DI cartridge doesn't seem to do much to the TDS, that's what needs to be replaced? 

 

I've read that using tap water can cause algae blooms, especially cyano. I did a water change and immediately had a big cyano bloom, so I assume the water was responsible. 

Cyano usually comes from too clean of a tank and super low nutrients, like undetectable phosphates and nitrates no? i think you need more information, like your tank parameters and new saltwater mix parameters to really determine what's causing your cyano bloom. 

[Tired]

Nope, it was the carbon. You're right that cyano (and some other pests) usually come from too clean of a tank, but that doesn't tend to happen overnight after a water change. I swapped out the carbon filter, which was overdue, and the cyano faded away. Gotta love simple problems.

[DevilDuck]

Reminds me to check my cartridges!

[Broseff]

On 12/17/2020 at 2:45 PM, Tired said:

Alright, thanks. I'll swap those out.

 

The DI filter isn't yet exhausted, it's got an inch or so left, but I think I'm about to exhaust it. I'm going to filter a whole bunch of water to keep for my plants. I have some fussy plants (Nepenthes pitcher plants, mostly) that don't like tap water, but they don't mind water with a few TDS worth of stuff in it. May as well use up what's left of the filter capacity storing up water for them. 

I know it's off topic, but I love nepenthes. I have a couple. I just buy water for them at the store.

[jservedio]

5 hours ago, Tired said:

Nope, it was the carbon. You're right that cyano (and some other pests) usually come from too clean of a tank, but that doesn't tend to happen overnight after a water change. I swapped out the carbon filter, which was overdue, and the cyano faded away. Gotta love simple problems.

Keep an eye on your membrane and be very proactive about changing your carbon block in the future. Your carbon block is by far the most important part of the RODI system since it is what is removing chlorine and/or chloramine which causes permanent damage to the RO membrane. Just a couple of weeks of run time with chlorine making it through is enough to destroy your expensive membrane.

 

You also really need a TDS meter - you can grab one off Amazon for like $15 or get a 2-stage one that gets plumbed right into your RODI system. Without one you have no idea if your fresh made water is good or not.

 

  

7 minutes ago, Broseff said:

I know it's off topic, but I love nepenthes. I have a couple. I just buy water for them at the store.

A $130 RODI machine will pay for itself on a 20g tank in just over 6 months if you are changing 5 gallons of water every 2 weeks and using about 1/3g in your ATO per day (what my 20g used) not counting the waste of time and gas. If you have the room, why would you waste your money?

[Clown79]

1 minute ago, jservedio said:

Keep an eye on your membrane and be very proactive about changing your carbon block in the future. Your carbon block is by far the most important part of the RODI system since it is what is removing chlorine and/or chloramine which causes permanent damage to the RO membrane. Just a couple of weeks of run time with chlorine making it through is enough to destroy your expensive membrane.

 

You also really need a TDS meter - you can grab one off Amazon for like $15 or get a 2-stage one that gets plumbed right into your RODI system. Without one you have no idea if your fresh made water is good or not.

Agree.when sediment filters get clogged it causes issues with the carbon block, if carbon blocks are exhausted it can damage the membrane and also causes DI to do all the work exhausting di faster.

 

I always used 2 carbon blocks. Regular carbon and then a chloramine block because regular carbon blocks don't remove chloramine effectively.

Chloramine is hard on the membrane and exhausts di fast.

[Broseff]

20 minutes ago, jservedio said:

A $130 RODI machine will pay for itself on a 20g tank in just over 6 months if you are changing 5 gallons of water every 2 weeks and using about 1/3g in your ATO per day (what my 20g used) not counting the waste of time and gas. If you have the room, why would you waste your money?

I'm just referring to watering plants. Like, I'm sure it pays itself off after awhile, but like when you're watering just a couple of plants it's not super necessary.