pH, Algae Problems and Tap Water

bulldogin04 · 11/22/2017, 07:20 PM

Ok Here's the deal. I recently got back into the hobby and setup my old 30 gallon cube. I got new lights (LED of course, bye bye old compacts), new reef octopus skimmer and went with my old trickle filter sump. Ran the tank through its break-in cycle over year with a small bio load, pair of clowns and a cleaner wrasse, plus artificial "purple" live rock (not recommended BTW).

After the first liberal break-in year, I started to notice a white slime algae and treated it like any other diatom break out; lights out for 2 days reduced the already conservative feeding. Yes, it would get knocked back but always managed to come back after a week or so. So I did what every other reef keeper does - Check your water parameters. I'm not a water quality nazi, but I don't neglect my tank mates cause that's cruel; but every time I checked things the only abnormal parameter was pH at 7.8. Ok, 7.8 is low, but not something to jump up and down about, time to go with some kalwasser. So here's where things get interesting.

From the start, I used distilled water by the gallon as my water source (yes, I recycled the plastic) and I read somewhere that the plastic in those jugs leaches out a certain chemical that cyano-bacteria like (totally bogus). I was starting to get paranoid at this point with such a persistent problem so I figured its time to go RO. When I switched to a 6 stage RO/DI water kit, I noticed that my pH was now dipping below 7.8 on occasion. That is something to worry about.

Now we go off the deep end in this story. I, unlike most people, have access to lab grade pH and DO meters (calibrated daily) and know the folks that work in the water utility. One day I bring in a grab sample from my tank and my tap and my RO water. Tank 7.8, tap water 6.8 and fresh RO water 6.2, YES 6.2! So I give the operations manager a call and set up a meeting and try to understand what is going on here.

Put on your thinking cap cause this is were the chemistry comes in. According to the Water Treatment Operations Manager, the water they put into their distribution system is about 7.5. The source water is a surface lake and not ground water. The source water coming in slightly acid and ranges from 6-6.8 but can vary a lot with precipitation events. The treatment process used here is chlorine disinfection, followed by ozone, then UV sterilization then chloramines (filtration? forget it!), followed by another dose of free chlorine for residual.

Q: So how do you go from 6.5 source water to 7.5 in distribution? A: Well we add sodium potash (KOH) to buffer and raise pH as well as adding phosphoric acid (H3PO4) for corrosion control in the water mains. Now this is making sense, the RO unit is removing all these items from the tap water hence the drop in the tap water pH as it exits the RO unit. However, the free hydrogen atom remains in solution from the phosphoric acid and will readily bind with atmospheric CO2 and forming carbonic acid (H2CO3). This keeps my pure RO water pH below 7. Normal RO water is going to go acid anyway, mine is just extra hungry for CO2.

Remember how I said the source water is from the surface, not ground water? The surface water is very pure, that's good right? Nope, it has absolutely zero buffering capacity; hence the large fluctuations in pH through out the water treatment process and in the end, the acid water coming out of my RO unit for saltwater mixing. Most salt mixes are designed to be mixed with water with a pH of 7 or greater.

So here's how I got my white slime algae / diatom problem under control. I have to continually add kalwasser at about 2 times the normal rate to maintain higher acceptable pH. The higher pH ranges have reduced the slime algae problem significantly. The added bonus is my leather coral is actually getting bigger, xenia are splitting and growing, calcareous algae are starting to grow. So after almost 2 years I finally have my tank water chemistry working right.

So the moral of the story is know your source water and water chemistry!

Thanks for reading

JamesZebedee · 11/23/2017, 11:50 AM

Interesting story. That's a curious bit of chemistry going on.

You are obviously very knowledgeable on these topics, so hoping i can ask a water filtration question:

I've seen that the consensus is that RO water is required for reefkeeping, but i don't fully understand why. I don't really want to use it, as I'm concerned by the amount of water which it wastes. The main thing it does is too soften the water.

I've done a search on this forum for people talking about RODI, and water hardness, and haven't found any detail of how hard water causes problems. In several places, people have said that hard water isnt actually a problem, and that the main risk is other goodies especially copper and zinc impurities.
I've obtained local water test results (attached) which show these metals to be below limits of detection, (Cu<0.02ppm). I filter my drinking water with a GAC filter, which should remove the part per billion volatile organic compounds from the water.

The report shows the Total Alkalinity Carbonate (TAC) as 153mg CaCO3/L. I believe this corresponds to 8.6 degrees GH.

Total hardness is 298 mg CaCO3/L . Do you know if this will cause a problem for my livestock? I'm starting off with a FOWLER tank.

Full report attached, (in catalan, but should be still readable.)

bulldogin04 · 11/24/2017, 11:19 AM

Looking at the report, it looks like you would be a good candidate for an RO/DI filter. There is nothing in there that is very alarming. Your water is hard at 8.1 pH and has some pretty good buffering capacity with the TAC at 153mg/L. The only worrying item is nitrates at 9.8 mg/l, it may be fine for you and me but in a reef it is bad news.

I have used hard tap water for my tank, many many years ago, and always had problems with invertebrates like LSP and SPS. Fishes, snails, crabs, shrimps were all fine, but I gave up trying on corals. I simply couldn't get good water quality to keep them (might have been inexperience too).

The danger you run using tap water is that evaporation concentrates all those low concentration chemicals and elements and you can't control whats going in. Even with regular water changes your water quality might not match what is required to keep the critters you want. Then again it could be fine.

Not to get your paranoia up but in the water/wastewater business is common to take a "representative" sample. Its not cherry picking the sample you send off to the lab but its cherry picking the sample you send to the lab. I trust the results in water quality reports but I take them with a grain of salt. In most places you can call your local utility and ask questions about the treatment process and I'm sure they would love to talk about it. I have toured a number of water treatment facilities over the years and I have found that I would only recommend RO/DI for use in the marine aquarium. I know some people have had great success with out it but I'm fairly sure almost all people with RO/DI water are successful.

I am still struggling with lower than ideal pH, I have finally got it up to 8.0 and my critters are happier. I think I still have too much CO2 in my house and that causes the lower pH. It could be coming from an oversized skimmer too. The battle never ends.

outy · 11/24/2017, 12:02 PM

We use RO/DI water in our reefs because we know what we have, laboratory grade pure water.

Tap water quality fluctuates greatly, some more then others. Most people do not test fully, and have no clue what they are dumping in their tanks. Can be done short term not long term.

outy · 11/24/2017, 12:04 PM

Quote:

Originally Posted by bulldogin04

my old trickle filter sump.

These are nitrate factory's and we generally avoid these.

sde1500 · 11/24/2017, 12:08 PM

Quote:

Originally Posted by JamesZebedee

Interesting story. That's a curious bit of chemistry going on.

You are obviously very knowledgeable on these topics, so hoping i can ask a water filtration question:

I've seen that the consensus is that RO water is required for reefkeeping, but i don't fully understand why. I don't really want to use it, as I'm concerned by the amount of water which it wastes. The main thing it does is too soften the water.

I've done a search on this forum for people talking about RODI, and water hardness, and haven't found any detail of how hard water causes problems. In several places, people have said that hard water isnt actually a problem, and that the main risk is other goodies especially copper and zinc impurities.
I've obtained local water test results (attached) which show these metals to be below limits of detection, (Cu<0.02ppm). I filter my drinking water with a GAC filter, which should remove the part per billion volatile organic compounds from the water.

The report shows the Total Alkalinity Carbonate (TAC) as 153mg CaCO3/L. I believe this corresponds to 8.6 degrees GH.

Total hardness is 298 mg CaCO3/L . Do you know if this will cause a problem for my livestock? I'm starting off with a FOWLER tank.

Full report attached, (in catalan, but should be still readable.)

Our use of RODI has everything to do with controlling exactly what goes into our tanks. RODI water is pure water. We then add salt to add back in exactly what is good for our tanks. There can be plenty of trace elements that are not good to a tank that will build up overtime and cause issues. It is not recommended.

JamesZebedee · 11/28/2017, 02:01 PM

Quote:

Originally Posted by bulldogin04

The only worrying item is nitrates at 9.8 mg/l, it may be fine for you and me but in a reef it is bad news.

I have used hard tap water for my tank, many many years ago, and always had problems with invertebrates like LSP and SPS.

Quote:

Originally Posted by outy

We use RO/DI water in our reefs because we know what we have, laboratory grade pure water.

Quote:

Originally Posted by sde1500

Our use of RODI has everything to do with controlling exactly what goes into our tanks. RODI water is pure water.

Thanks for the info, guys. Given that I'm starting my marine career with a FOWLER tank, I think I'll have a go with just carbon filtration at present. I'll spend some extra money on testing equipment to monitor my hardness, etc.

Turbomark · 11/28/2017, 04:47 PM

Don't worry about your hardness this isn't a freshwater tank, when you add salt to the system that will take care of itself. Pull together $100 and buy a simple rodi system. Remember that when your tank evaporates water you'll be replacing it with tap water and therefore concentrating all of those impurities. If you run the tank with tap water you'll soon be battling issues with algae and other things. The fish pollute the water enough as is, they don't need any additional help.

Sent from my Nexus 5X using Tapatalk

11/22/2017, 07:20 PM	#1
bulldogin04 Registered Member Join Date: Jun 2005 Location: SB, INDIANA Posts: 2	pH, Algae Problems and Tap Water Ok Here's the deal. I recently got back into the hobby and setup my old 30 gallon cube. I got new lights (LED of course, bye bye old compacts), new reef octopus skimmer and went with my old trickle filter sump. Ran the tank through its break-in cycle over year with a small bio load, pair of clowns and a cleaner wrasse, plus artificial "purple" live rock (not recommended BTW). After the first liberal break-in year, I started to notice a white slime algae and treated it like any other diatom break out; lights out for 2 days reduced the already conservative feeding. Yes, it would get knocked back but always managed to come back after a week or so. So I did what every other reef keeper does - Check your water parameters. I'm not a water quality nazi, but I don't neglect my tank mates cause that's cruel; but every time I checked things the only abnormal parameter was pH at 7.8. Ok, 7.8 is low, but not something to jump up and down about, time to go with some kalwasser. So here's where things get interesting. From the start, I used distilled water by the gallon as my water source (yes, I recycled the plastic) and I read somewhere that the plastic in those jugs leaches out a certain chemical that cyano-bacteria like (totally bogus). I was starting to get paranoid at this point with such a persistent problem so I figured its time to go RO. When I switched to a 6 stage RO/DI water kit, I noticed that my pH was now dipping below 7.8 on occasion. That is something to worry about. Now we go off the deep end in this story. I, unlike most people, have access to lab grade pH and DO meters (calibrated daily) and know the folks that work in the water utility. One day I bring in a grab sample from my tank and my tap and my RO water. Tank 7.8, tap water 6.8 and fresh RO water 6.2, YES 6.2! So I give the operations manager a call and set up a meeting and try to understand what is going on here. Put on your thinking cap cause this is were the chemistry comes in. According to the Water Treatment Operations Manager, the water they put into their distribution system is about 7.5. The source water is a surface lake and not ground water. The source water coming in slightly acid and ranges from 6-6.8 but can vary a lot with precipitation events. The treatment process used here is chlorine disinfection, followed by ozone, then UV sterilization then chloramines (filtration? forget it!), followed by another dose of free chlorine for residual. Q: So how do you go from 6.5 source water to 7.5 in distribution? A: Well we add sodium potash (KOH) to buffer and raise pH as well as adding phosphoric acid (H3PO4) for corrosion control in the water mains. Now this is making sense, the RO unit is removing all these items from the tap water hence the drop in the tap water pH as it exits the RO unit. However, the free hydrogen atom remains in solution from the phosphoric acid and will readily bind with atmospheric CO2 and forming carbonic acid (H2CO3). This keeps my pure RO water pH below 7. Normal RO water is going to go acid anyway, mine is just extra hungry for CO2. Remember how I said the source water is from the surface, not ground water? The surface water is very pure, that's good right? Nope, it has absolutely zero buffering capacity; hence the large fluctuations in pH through out the water treatment process and in the end, the acid water coming out of my RO unit for saltwater mixing. Most salt mixes are designed to be mixed with water with a pH of 7 or greater. So here's how I got my white slime algae / diatom problem under control. I have to continually add kalwasser at about 2 times the normal rate to maintain higher acceptable pH. The higher pH ranges have reduced the slime algae problem significantly. The added bonus is my leather coral is actually getting bigger, xenia are splitting and growing, calcareous algae are starting to grow. So after almost 2 years I finally have my tank water chemistry working right. So the moral of the story is know your source water and water chemistry! Thanks for reading

11/24/2017, 11:19 AM	#3
bulldogin04 Registered Member Join Date: Jun 2005 Location: SB, INDIANA Posts: 2	Looking at the report, it looks like you would be a good candidate for an RO/DI filter. There is nothing in there that is very alarming. Your water is hard at 8.1 pH and has some pretty good buffering capacity with the TAC at 153mg/L. The only worrying item is nitrates at 9.8 mg/l, it may be fine for you and me but in a reef it is bad news. I have used hard tap water for my tank, many many years ago, and always had problems with invertebrates like LSP and SPS. Fishes, snails, crabs, shrimps were all fine, but I gave up trying on corals. I simply couldn't get good water quality to keep them (might have been inexperience too). The danger you run using tap water is that evaporation concentrates all those low concentration chemicals and elements and you can't control whats going in. Even with regular water changes your water quality might not match what is required to keep the critters you want. Then again it could be fine. Not to get your paranoia up but in the water/wastewater business is common to take a "representative" sample. Its not cherry picking the sample you send off to the lab but its cherry picking the sample you send to the lab. I trust the results in water quality reports but I take them with a grain of salt. In most places you can call your local utility and ask questions about the treatment process and I'm sure they would love to talk about it. I have toured a number of water treatment facilities over the years and I have found that I would only recommend RO/DI for use in the marine aquarium. I know some people have had great success with out it but I'm fairly sure almost all people with RO/DI water are successful. I am still struggling with lower than ideal pH, I have finally got it up to 8.0 and my critters are happier. I think I still have too much CO2 in my house and that causes the lower pH. It could be coming from an oversized skimmer too. The battle never ends.

11/24/2017, 12:02 PM	#4
outy Moved On Join Date: Oct 2004 Location: auburn CA Posts: 4,021	We use RO/DI water in our reefs because we know what we have, laboratory grade pure water. Tap water quality fluctuates greatly, some more then others. Most people do not test fully, and have no clue what they are dumping in their tanks. Can be done short term not long term.

11/28/2017, 04:47 PM	#8
Turbomark Registered Member Join Date: Jul 2013 Posts: 81	Don't worry about your hardness this isn't a freshwater tank, when you add salt to the system that will take care of itself. Pull together $100 and buy a simple rodi system. Remember that when your tank evaporates water you'll be replacing it with tap water and therefore concentrating all of those impurities. If you run the tank with tap water you'll soon be battling issues with algae and other things. The fish pollute the water enough as is, they don't need any additional help. Sent from my Nexus 5X using Tapatalk