Phosphates or Silicates slipping past TDS meter?

[jostafew]

Hey everyone, I've got a question re. TDI and phosphates / silicates, but first a little background: Ever since I moved from Langley to Abbotsford my tanks have gone to crap with cyano and red/brown algae everywhere (one moved, the other one in the my work office was undisturbed). Everything is the same except for the source water. TDS meter showed reading on source water of about 15-20ppm in Langley which went to 25-120ppm in Abby, water tasted kinda funky too. TDS leaving the RODI went from 0 to 1-2 after moving. Ran this for a while and noticed the problem appearing. Been about 8 months of this.

Ok, changed the first three stages (mechanical and carbon), and DI stage of the filter, TDS on the output side now down to 0 again. Ran that for a couple months, no change (algae that I physically removed had all regrown).

Started running rowaphos in a reactor and another water change, junk grew back just as fiercly...

Down to the question in the subject, will problematic phosphates and/or silicates show up as TDS for my meter to detect or is it possible that junk is slipping through because I didn't change the RO stage of the filter (didn't change because TDS now reading 0ppm)? I'd like some feedback before I throw money at a full set of filter elements.

Thanks in advance

[Torx]

TDS is PPM. 0 tds on your meter does not mean 0.00 ppm. Just means that it is less then 1.00 ppm. So yes, problematic disolved solids such as phosphates could still be in the water. Plus the time water sits will increase as well.

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[denny_C]

although unless your tank is tiny the small amount of phosphates you add is but a blip on the radar when compared to other po4 sources.

[hillegom]

Test your water after the ro part and before the DI. The DI reduces the TDS to 0 until it is exhausted. You don't need any other filters to do that. Problem is DI costs a lot so u only use it to give the water a final polish.
Your RO filter should bring your water to at least 98% TDS free.(actually varies, depending on the gpd figure of your ro) If you start with 25ppm it should read 0 after the ro.
Your prefilters will take out the particulates first, then some dissolved solids.
Your TDS meter will only read dissolved solids, not particulates. I do not believe any dissolved solids will "sneak" past the meters ability to read them.

[hillegom]

I agree with the above, both posts.
Depends on your meters ability, how accurate it is.
However, the DI will take out the ppt until it is exhausted.

[StirCrazy]

no they will not register on the TDS meter.

Steve

[jostafew]

You're right Torx, 0 indicated TDS does not = 0ppm

Denny, I'm assuming that you're saying the amount of Phosphate that might be getting through is a small amount compared to other sources... Such as overfeeding & fish poop I'm assuming? My main system is 50gal total volume, in a 35gal shallow reef display with open top. I put about 5gal of makeup water through it a week. Office tank is 8gal nano, with solid lid, maybe 1 gal a month? Both are what I would consider lightly stocked.

Stircrazy, thanks for confirming

[reefwars]

You're right Torx, 0 indicated TDS does not = 0ppm

Denny, I'm assuming that you're saying the amount of Phosphate that might be getting through is a small amount compared to other sources... Such as overfeeding & fish poop I'm assuming? My main system is 50gal total volume, in a 35gal shallow reef display with open top. I put about 5gal of makeup water through it a week. Office tank is 8gal nano, with solid lid, maybe 1 gal a month? Both are what I would consider lightly stocked.

Stircrazy, thanks for confirming

Yes would be very small in comparison . Since this has been a long battle for you what have you ruled out so far? As far as a cause of cyano really there could be many. Are corals suffering?

[jostafew]

Hey reefwars, thanks for the interest in helping me get to the bottom of this. To be honest I haven't done a ton of troubleshooting. I've been in the new house for a year, and after getting the tank moved in (and sump plumbed into the garage) it's been on autopilot for the most part. Top off the freshwater, occasional checks of Calc and Alk, feeding fish etc. minimal water changes, probably not maintaining the skimmer as well as it should be. I had a diatom outbreak at one point (cloudy water) so I picked up a UV sterilizer and ran that for a month or so, cleared it up and no problems with that since. Trying to learn more about RO/DI systems and the consequences of old filters is part of that troubleshooting :wink:

To answer your other question, yeah between being temporarily setup at my mom's house (between selling the condo and moving into this house) and now the nuisance algae situation the corals are definitely suffering unfortunately.

[reefwars]

have you tried doing a chemiclean to help get ahead ?

[jostafew]

No, I've never done a chemiclean. Closest I've come has been a 12 day complete blackout in my war against the dynos....

Will do a little reading on Chemiclean. If/when I start with a fresh batch of filter elements that might make sense to blow up what's in there and replace with a big ass WC made up of new water

[reefwars]

No, I've never done a chemiclean. Closest I've come has been a 12 day complete blackout in my war against the dynos....

Will do a little reading on Chemiclean. If/when I start with a fresh batch of filter elements that might make sense to blow up what's in there and replace with a big ass WC made up of new water

That would be my plan as well :) several small things together done slowly and you can be clear of this in a couple of weeks.

[asylumdown]

Just an FYI, Abbotsford gets its drinking water from 3 sources. Most of it comes from Norrish Creek and Cannell Lake, but at peak demand times they supplement the drinking water coming out of your pipes with water from the Abbotsford-Sumas Aquifer. A good friend of mine is presently doing his PhD on plumes of agricultural contamination in the Abbotsford-Sumas aquifer, and Abbotsford-Mission Water Services has published documentation acknowledging the nitrate problem with water from those wells. It's severe enough that they are unable to use some of their wells for years at a time because the levels are way over the legal limit for human consumption, and WAAAAAAAAAAAY over the acceptable limit for a reef tank. Abbotsford also adds chloramines to all the water from all three sources before sending it out in to the pipes.

An RO membrane won't do much to remove chloramines, it's the carbon stage that does that I'm pretty sure. I also think it will exhaust the carbon quite a bit faster than if it was processing water that did not have chloramines (I'm not sure if Metro Vancouver uses them, which is where Langley gets its water). Depending on when you changed your RO stages and how much water they've made since you've lived in Abbotsford, your RO unit may have been letting both chloramines and trace amounts of agricultural run-off in to the tank for months.

If I were you I'd get an RO unit with an extra carbon stage (or a chloramine specific stage if such a thing exists) before the RO membrane and start doing large water changes. I'd also nuke the existing cyanobacteria with a product like chemiclean as Denny suggested. People will tell you that cyano is the result of you adding too many nutrients, but what people don't realize is that cyanobacteria fixes nitrogen and carbon directly from the atmosphere (in fact it's one the most important nitrogen fixing organisms in all of evolutionary history), so you could stop feeding your tank for a month and the the cyano will actually continue to eutrophy the system all on its own. It certainly capitalizes on excess nutrients when available, but once it's established it can add organic matter and nutrients to your system just from metabolizing chemicals available in the air (plus a tiny bit of phosphate).

I have a working hypothesis that you'll never be able to get ahead of a nutrient problem with cyano present, as the cyano produces it as much as capitalizes on it, but that's for another thread...

[jostafew]

Wow, thanks for the background, it's much appreciated! My current RODI system has a 10micron mechanical filter followed by a 5micron carbon block and a 1micron carbon. They were both changed a couple months back but in order to really squash this one I'll be starting with a fresh set top to bottom.

I'm going to pass your reply on to my wife; last year she read somewhere that Abbotsford has some of the best water in the lower mainland... I tried to tell her that compared to Langley where we were it is terrible. At one point last summer we could fill the tub and it would be noticeably colored, it's always tasted dirty, and my TDS meter indicates on average 10x the dissolved solids in the tap water. Despite all that she wouldn't let go of that article on water quality hahah.

[asylumdown]

Yah compared to Vancouver Metro, Abbotsford has some issues. I think you *can* have really good water, but it all depends on what mix and from what sources you're getting out of your tap at that particular moment. Obviously it's always safe for human consumption, but 'human safe' and 'reef safe' have different thresholds.

The 'legal limit' for nitrate contamination is 10ppm, but that's Nitrate reported as Nitrogen (a weird yet standard practice in water treatment and some areas of chemistry), which is actually closer to 44ppm nitrate reported as nitrate, which is how we talk about it in the hobby. The good news is that the average nitrate levels from the other two sources are both below 1ppm, and Abbotsford publishes a report indicating that they only get 5% of their water from the aquifer wells per year (none of which have nitrate levels acceptable for a tank), but that's an average for the whole system over a year. Moment to moment you never know what the mix is coming out of your taps.

Interestingly, the other element that routinely tests above the 'legal' limit coming out of the aquifer wells is manganese, which just so happens to be critical to oxygen evolution during photosynthesis. I haven't been able to find anything that showed elevated manganese encourages the growth of cyanobacteria (though I haven't looked all that hard), but people have been testing cyanobacterial mats as a zinc and manganese remediation technology because they're really good at sucking it up. Food for thought anyway.

Anyway I think you're on the right track, good luck!