Mustard algae questions

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skillset

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May 3, 2007
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Central NJ
1. Seems like you have to expose toys, hoses, nets, etc to mustard shocked pool water. Does this include running the heater, as well? Is there a concern about running high Cl water through a heat pump heater?

2. If left untreated, meaning maintaining Cl at normal operating levels for your CYA, will mustard algae typically spread?

Just got off of one pool issue and now have the seemingly common issue of determining whether I have pollen/dirt or mustard algae. My pool blaster has the sand/silt bag which I think is about 8 microns and this sandy darkish substance at the pool bottom vacuums up with the pool blaster but I see it coming out the sides in a cloud so it comes back. Even put a 5 micron filter over the pool blaster's bag and seems like the material won't be caught. I'm going to vacuum it to waste today.
 
this sandy darkish substance
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Doesn't really describe mustard algae which, when brushed, will billow up as a yellow-greenish cloud and not re-settle very much. It will grow right back in the same place which often leads folks to think it has resettled exactly where it was but that's not the case.
 
Anywhere algae spores might be has to be exposed to high chlorine. That includes the heater. Most people don;t have a bypass, so the high FC water goes through the heater when its being SLAMmed, and I haven't seen any hysterical posts saying the heater sprung a leak. pH is another story. But I digress.

Have you considered adding DE to your sand filter?
 
Thanks for the reply.

I just cleaned the pool. Vacuumed to waste by hand underwater - what fun! - tried to move as quickly as possible since the water drains fast. Took about 2" down in about 15/20 minutes. Nothing on the walls but never had anything on the walls given the pool is fg. Bottom had clumps (irregular shaped - a bit bigger than a jellybean) of brownish looking formations that instantly disintegrate when touched. Like a puff of smoke. So, couldn't tell if it felt slimy, gritty, or mushy. I'd say it was in about 50% of the pool - both the deep end (only 6') and the shallow end. Not much in the middle strangely. Moving with the hose got it all pretty quickly. Pool is now very clean - not a speck anywhere. Water clarity is ok - not what i'm used to. From above, looks fine. From underwater, I can see across the 33' length but not 100% clear.

Latest readings from an hour ago:
CYA: 40-45
Ph: 7.5
Cl: 7.5
alk=75 (threw in some baking soda to raise a bit)

Pump shut off about an hour ago so will see if anything comes back. If it does, I'll start shocking after the weekend at mustard doses. In any event, will see what my chlorine loss is overnight.

I do use DE in the filter. Richard (chem g) recommended a slime bag. I ordered it but forgot to get an attachment, so need to get that!
 
I forgot to do the OCLT test last night.

The pool is a bit cloudier than yesterday. Sigh. I seem to be losing ground. A couple of these clumps returned but just a few. Vacuumed to waste which only took 5 minutes. Backwashed and put DE in filter and will run 24x7. I went to home depot last night and got a PVC part to hook up the slime bag.

Couple of questions:

1. I have 2 returns - the slime bag is now attached to one. I blocked the other one off, but now, of course, not getting top-of-water flow. Am I better off with this situation OR unblocking one return to get flow ?

2. I guess the slimebag is working the way it needs to, but I'd have expected to feel some water coming out of it. But, I really don't. Also the top corner is out of the water. Guess all of this sounds right to those who've used the slime bag ? Pressure is the same with or without the slime bag attached.

3. Since the water is a bit cloudy, do folks recommend normal shock levels or mustard shock? I'm thinking mustard given the problem described. I will start the process tonight after sundown.

Thanks!
Marc
 
I'd keep the other return open for circulation. The slime bag is a large surface area compared to the opening of the return so you generally won't feel water flow coming from it -- that is normal. If the bag is inflated and if you push it in then it pops back out, then you know there is at least pressure in the bag and can assume there is flow going through it.

However, not seeing the pressure go up at all when only the Slime Bag is attached and the other return is turned off doesn't make sense. Even without the Slime Bag, if you turn off one return you normally would see pressure rise at least somewhat. That's strange.

If you do a high shock level, make sure you lower the pH first to at least 7.2 (but not below 7.0).
 
Thanks, Richard. I opened up the one return. Before pressure with just the slime bag was 20 (maybe just slightly more - but not 21). With the one return open, pressure still 20 (but maybe just slightly less - but not 19).

Thanks for the tip on the Ph - I'm assuming this is to prevent staining? My pool has always gravitated to 7.2 (or less) and I find myself adding Borax a few times each season. Never had this high a Ph before (not that 7.5 is very high). Current reading right now is 7.5. I believe the pool got this high from a few partial drain/refills where the hose to fill the pool, as well as the return jets created a lot of splashing which I believe raises Ph. I've never used Dry Acid before (I don't have MA - never ever bought it all the years, but have Dry Acid that's a few years old). Looks like I'll need to add about 12 oz of that according to PoolCalculator to bring down Ph. Sure hope that doesn't contribute to more cloudiness as I've never used the stuff.
 
Yes, the lower starting pH is to prevent metal staining when the pH rises from adding a lot of chlorine, but it also helps reduce cloudiness that may occur from over-saturation of calcium carbonate depending on your starting level. Run the pump 24/7 and the Slime Bag should capture anything in the water that is making it cloudy. It filters down to 1 micron. Though that's overkill, there may be some problem with your filter not removing fine particulate matter.
 
Thanks, again. I took a swim and the pool is better than this AM when I put the slime bag in. I can see across the entire pool. Decent difference in 6 hours. I may just let the slime bag work for a few days (without shocking) to see if that's all I need. Seems like it's working - cautiously optimistic. Thoughts about holding off shocking?

My CH is very low, practically non existent at 40. The pressure gauge and sand in the filter are also new - trying to rule out things over the past month.
 
Yes, just keep filtering rather than shocking. It does sound like the cloudiness was a filtration problem, not algae continuing to grow. The more definitive test for whether shocking is needed is the OCLT. If you don't have overnight chlorine loss of significance, then filtering rather than shocking would seem more appropriate.
 

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Thanks. I put a jug of Clorox in last night and Cl was 15 - not exactly shock level but wanted to keep Cl on the higher side. This morning was 15, too, so passed OCLT. Went in pool and it's looking much better - almost 100%. Just a slight haze - I can read the word slime bag on the slime bag from underwater from the deep end.

Between the backwashed filter and slime bag - less than 24 hours a very big difference. Thank you!

How do I know when to clean the slime bag? The pressure is up 1 lb from last night. Prior to the backwash and the slime bag install yesterday, filter hadn't seen any pressure rise in about a week.
 
As described in the Slime Bag FAQ:

When do I replace my Slime Bag™?

The Slime Bag™ can be cleaned many times before it requires replacement. As discussed above, the pressure will increase, as the bags get dirtier. You should replace when you have a 10 to 15 pound pressure differential which cannot be rectified be cleaning. Replace your Slime Bag™ if it becomes damaged or retains water when held outside of water.
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It sounds like you've got a ways to go before you need to clean it.
 
Update. Still battling a problem, but after some new observations, I've come to believe the issue I have is similar to what's in this post:

white-chalky-residue-on-fiberglass-pool-t31062.html

Here's why: After 2 days of non-use of the pool and the slime bag in operation with filtering 24x7, the pool water cleared. I mean it was 100% - like glass I've always been accustomed over the years, but was elusive this season. I was thrilled! But, 20 minutes after being in the pool, the haze set in. There were no signs any longer of any dark spots on the pool floor - the pool was completely clear and debris free. So, just moving around the pool clouded it. Upon further examination, I noticed that brushing it caused a white haze to emit from some (not all) of the sides/bottom. The more I brushed, the cloudier the pool became. The next day, the pool would clear to about 80% when I repeated the brushing process. I guess if I left it undisturbed it would have cleared all the way. So, over the past 3-4 days, I've backwashed the filter, cleaned the slime bag. The slime bag when touched also emitted the white haze until it was cleaned. I had been hoping that eventually the slime bag and filter would eventually work. Tonight, I found that above post is what exactly what I have: cloudy pool caused by scaling that also has symptoms, once in awhile, of white flecks floating on top. Today, I had the white flecks.

Given my current CH is practically non-existent, I'm assuming I need to add CH right away. But, not sure if I should add a scale product or not. I thought scale would be caused by too much CH not too little? Anyway, last time I added something in (Alum floc) it was a disaster. Perhaps getting CH up to level and then scrubbing could remove scale without putting in another chemical? In the past, I've tried to add CH but I believe always had too much Metal Magic in the water which interfered with the CH. Since I've done a few drain/refills in the last 2 weeks and have been using the Culator product, I haven't had a stain and thus have not added MM. So, I believe the current levels of sequestrant in the pool is probably quite low now.

I don't know if I should continue this thread or begin just posting on the above thread, but I'd really like to get a path forward. Let me know your thoughts.
 
The gelcoat in some fiberglass pools has calcium carbonate so if that is the case then not having any CH can result in dissolving of the calcium carbonate in the gelcoat. However, the calcium carbonate won't show up as cloudy unless it is over-saturated which isn't your situation. Perhaps the dissolving of the gelcoat releases other components of the fiberglass pool surface and those are insoluble and cloud the water. That would explain why the manufacturer in the other thread said to increase the CH level. We normally recommend having CH in fiberglass pools for this reason.

I don't know if adding CH to your pool will work at this point in time or if it's too late (i.e. the surface is deteriorated to the point that it will keep falling apart releasing more cloudiness), but you can try it. Also, the stain & scale control mentioned in the other thread may help to dissolve existing scale or prevent new scale -- the thing is that a low CH is the opposite of getting scale so this is confusing to me.
 
Thanks, Richard. I've been posting on that other thread and think I'll give the CH a try first. Hope I didn't ruin the gelcoat by years of keeping the CH low. I've googled fiberglass pools and chalky and seems like it's there quite a few people with the issue.

It's confusing to me how one gets scale from LACK of CH, but there's no doubt this white residue is some sort of a "scale."

Do you know if a 6 year old tub of CH would still be good if kept in an outdoor shed ?
 
The calcium chloride should not go bad. It might clump up and not dissolve well, however, but you can see what it looks like.

A low CH won't cause scale. It does the opposite, causing the calcium carbonate in some gelcoat to dissolve thereby weakening the structure of the surface. That's what makes this confusing where people call it scale. Yes, if the saturation index is too high one can get scale, but that doesn't sound like your situation.
 
Ok - so if there is no calcium carb in the gel coat, then the calcium is not likely to help? I think i read somewhere that San Juan doesn't use calcium carb but I can't be sure. I may give them a call on Monday but their pool guidelines do recommend a healthy level of CH. Confusing indeed but one things for certain is that the residue is present.

If you we're in my shoes, what would you do next? Is it possible that other factors, like a higher ph or high Cl levels could be enabling the residue? Pool likes to run at 7.2 ph but because of the drain refill, it's 7.6. I wonder if I should try lowering ph - or am I grasping?
 
Thanks - will contact them this week.

In the meantime, I dug up my owners manual for the pool. Recommended CH is 300-350 and Ph is 7.2-7.6 and Cl is 1-3. We all know here that Cl is dependent on CYA so we need to ignore that recommendation.

If I do want to lower the Ph a bit by using dry acid (never had a situation where I lowered Ph so never used MA or Dry Acid), will the addition of Calcium Chloride and Dry Acid cause an issue? Obviously, I wouldn't add CH and acid at the exact same time, but if done a few hours apart, do you think this would cause me a further clouding issue?

Appreciate all your responses!
 
Those two don't interact so no problem adding one after the other if done over a return flow to ensure thorough mixing. I'd add the acid first to lower the pH since that will reduce the chance of cloudiness from adding the calcium chloride where locally the CH level will get high until it gets more thoroughly mixed. I find that I usually need to brush the pool because the calcium chloride pellets don't dissolve instantly, but they don't take too long to dissolve.
 

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