Distilled water?

[dava6711]

Hey Reefcentral

I need some advice. I've currently got a 45 gallon saltwater aquarium that's been setup for approx two years. But it's been plagued with problem algae from pretty much day one, cyanobacteria, hair algae etc.
For the last two months I've been cooking the liverock in a plastic trash can that's manufactured from HDPE.
All the livestock has been moved on to other reef keepers but the aquarium is still running with only a sand bed while I try to figure this out?
I have a deltec MCE600 with a brand new DCS600 pump and the aquarium is currently lit by an aqua-medic aquasunlight 250w (the metal halide has been turned off though and only the 4 actinics are illuminating the aquarium). I run activated carbon on the aquarium 24/7 that's housed within the media chamber of the skimmer that's religiously replaced every two weeks.
All makeup water comes from an RO/DI unit that has a prefilter, carbon block and two DI filters. All the make up water is stored in a HDPE trash can. I've got two TDS meters (one inline and the other handheld), the inline TDS meter shows that the water leaving the final DI pod has a reading of zero TDS (my tap water that feeds the unit has a TDS of 78ppm). My handheld TDS reading from my processed/stored water has a reading of 0.01ppm.
I've got a hanar instruments HI 736 phosphorus checker which shows my tap water has very high phosphate levels as they measure 200ppb (which are as high as the unit can measure, the phosphate levels are likely much higher!

So even though my tank is devoid of all livestock including liverock and only has a 1/2" sand bed, I put zero food into the aquarium and haven't since the day I removed all the livestock, the substrate is still covered in red slime algae. What's causing this, could my water container be leaching phosphates at it has 0.01 ppm reading (it's not a food grade bin).

So I'm thinking about ditching the RO/DI unit and purchasing distilled water (I'm still researching vendors to source distilled water that hasn't been exposed to copper during the distillation process) as it's extremely pure, could this help? I mean the problem has to be RO/DI as its the ONLY thing going into the aquarium, is distilled water purer than RO/DI water?

Or is if the bin, if you think it could be the bin where I store my water is there a water butt available that I can purchase that's absoloutly inert and will not leach anything?

Thanks for any advice offered.

 

[milesmiles902]

Reply

Reply

Well....RO/DI water will help if there are a lot of NO3⁻ and PO4^3- in your tank.

There is always this link....

Cyanobacteria-How to Fix it

I personally have never tried it, but I can imagine it would work. Since cyanobacteria needs light to survive.

I would give it a shot, since there is no coral or fish in your tank..

 

[dava6711]

Thanks for the reply friend. I'm already using RO/DI but I'm still getting lots and lots of cyano all over my substrate, so I'm unsure if my RO/DI is struggling to remove all the phosphate from my tap water as my tap waters phosphate levels are excessive? But I'm fairly certain cyano is caused from a build up of organics more than elevated levels of phosphate so where is the build up of organics coming from? I can't be 100% about the phosphste levels of the filtered water in my trash can as water that's very pure (i.e. RO/DI water is difficult to test accurately). However, the inline TDS meter measures a TDS of 0.00ppm but my handheld TDS meter measures my filtered water in the trash can as being 0.01ppm. So, is the culprit for the cause of cyano the trash can, the RO/DI unit or something else? This is why I'm thinking of purchasing distilled water as it's allegedly the purest water you can buy?

 

[Mark...]

Isn't 0 TDS also reflex phosphate? As in none from the tap post treatment?

Any areas in the sump that could be an issue?

My gut would say change out the sand bed, clean up everything and start with your fresh ro/di water and see how it goes...

 

[dava6711]

The sand bed was thoroughly cleaned and a substantial part completely replaced! I'm not entirely sure what you're referring to with 'reflex phosphates'? I don't have a sump but I do have an internal weir where I hang my skimmer from and house the return pump. I've decided to substantially upgrade my RO/DI unit and add an additional carbon filter which will give me two carbon filters in total and add another two DI filters which will give me three DI filters in total. If that doesn't rid me of my cyano problem then I'm sure nothing else will lol?

 

[Mark...]

I meant to say reflect...in others words if TDS is 0, then no phos from the ro/di.

I've read certain poor quality carbon can release phosphates...

 

[wbrinker]

I thought 0 TDS was phosphate clear

 

[dava6711]

I thought 0 TDS was phosphate clear

Not always, you can have 0ppm TDS and still have phosphates in the water, granted they'll be low though!

 

[dkeller_nc]

I run activated carbon on the aquarium 24/7 that's housed within the media chamber of the skimmer that's religiously replaced every two weeks.

Actually, depending on the type/brand and the quantity of GAC you're running, this may be the primary source of your algae problem. Also not to be discounted is an extremely dirty sand bed that's leaching phosphate/nitrate back in to the tank water. But most activated carbon has some level of phosphate that will re-dissolve into sea/fresh water, the quality of the GAC is the determining factor about how much will be released.

Unless your RO membrane is compromised and your DI cartridges are either extremely low-grade resin or exhausted, the phosphate isn't coming from your water purification system.

And it's also unlikely that it's coming from your water storage container, presuming that it's actually HDPE and not a mixed resin or "post consumer recycled" plastic. The HDPE raw material/molding process is fairly unusual as far as plastics are concerned in that it doesn't contain additives such as plasticizers.

 

[dava6711]

Actually, depending on the type/brand and the quantity of GAC you're running, this may be the primary source of your algae problem. Also not to be discounted is an extremely dirty sand bed that's leaching phosphate/nitrate back in to the tank water. But most activated carbon has some level of phosphate that will re-dissolve into sea/fresh water, the quality of the GAC is the determining factor about how much will be released.

Unless your RO membrane is compromised and your DI cartridges are either extremely low-grade resin or exhausted, the phosphate isn't coming from your water purification system.

And it's also unlikely that it's coming from your water storage container, presuming that it's actually HDPE and not a mixed resin or "post consumer recycled" plastic. The HDPE raw material/molding process is fairly unusual as far as plastics are concerned in that it doesn't contain additives such as plasticizers.

Thanks for this great post friend. I suppose the quality of my GAC could be called into question as I purchased a very, large box full from a reputable online koi supply company, I shopped around and got it for a terrific price (I was surprised that I received as much as I did for the price I paid)! So this could be a factor?

I never even knew that poor quality GAC was capable of leaching phosphates into the water column?

The black bin that I store my RO/DI in is definitely manufactured from HDPE as it has a stamp on the bottom stating so, however I've no idea if it's been made from recycled plastics or not, is this even possible to determine?
I've been recommended by members from this site to use food grade storage containers, what's your experience of this?

My RO/DI now has a brand new 50gpd membrane with matching flow restrictor, replaced all the prefilters, added another carbon filter and added two additional DI filters (giving me three DI filters in total), I also installed a DI bypass to increase the life of DI filters.
A little over the top but my tap water has crazy high levels of phosphate.

Thanks for your input

 

[TY31088]

What's the phosphate level of your fresh saltwater?

 

[dava6711]

What's the phosphate level of your fresh saltwater?

Not sure, I performed a water change this morning using the water from my newly upgraded RO/DI but didn't bother to measure the phosphate level. I'm gonna prepare a fresh batch tomorrow so I'll be able to take a reading then.........

 

[dkeller_nc]

Thanks for this great post friend. I suppose the quality of my GAC could be called into question as I purchased a very, large box full from a reputable online koi supply company, I shopped around and got it for a terrific price (I was surprised that I received as much as I did for the price I paid)! So this could be a factor?

I never even knew that poor quality GAC was capable of leaching phosphates into the water column?

Well, perhaps I shouldn't have used the term "quality" - a better one might be "better for reef tank use". There are 4 primary, common sources for making granular activated carbon: wood chips, coconut husks, animal bones, and coal.

Each of these sources of organic material generates carbon designed for specific tasks, and the actual processing of the organic material into the GAC also plays a big role in its properties.

For general water filtration (to remove taste, odor and color compounds), so-called "coconut carbon" is typically used. It generates a GAC that is fairly uniform, has a large pore size, is very low in heavy metals and is pretty inexpensive. However, it also typically has a fairly high level of phosphates. This material is often packaged and sold as aquarium filtration carbon, and is great to use if you need a lot of carbon to remove a lot of organics and don't really care about phosphates. Curing fresh live rock would be an example.

The high-grade stuff is made from coal. It typically has the lowest phosphate content, is highly uniform, and is very hard, so it doesn't fracture into a lot of tiny particles when it's used in industrial processes. But the highly pure grades of coal carbon is considerably more expensive than most other kinds, so it may be most appropriate for an established reef tank where one is trying to remove trace amounts of organics rather than trying to correct a problem (such as a tank crash). Seachem's Matrix Carbon is an example of this kind of carbon.

As for your trash can, it's fairly unlikely that it's a significant source of phosphate in your seawater. The carbon and/or nutrient accumulation in your sandbed is of considerably greater concern. One reason I say this is that your water container has a tiny amount of surface area compared to your sandbed/GAC.

 

[dava6711]

That's good to know about the GAC, I'll invest in seachem GAC from now on. My sand bed is immaculate now as the tank is empty apart from the sand bed which is vacuumed twice a day. I'm pretty sure the cyano is beginning to die back because when I view the aquarium in the morning there's barely any visible on the sand bed so I think I've turned the tide. I'll probably leave the sandbed vacuuming for several days to see if it returns, if it doesn't then I reckon I've won lol?

 

[shrimpgal]

Lights out for 3 days and increased water flow did mine in:thumbsup: