New Here, Need Help! Lighting For Planted Tank. Algae Bloom

This is going to be a quick response and thus brief, as I have to log off momentarily, but if I post something then it will be a subscribed thread and I can keep on top of things.
 
From the data provided, my first suggestion is that the light is too intense, and somewhat the wrong spectrum.  I am assuming it is T5 HO, and likely more geared to marine tanks than freshwater planted.  Algae is quick to take advantage of lighting that is beyond what the plants need, or is not providing a balance of red/blue/green, or an imbalance with light/nutrients.  Too much light, too little light, too many nutrients, too few nutrients...any of these can encourage algae because the higher plants are a bit more demanding.
 
It will help if you can provide more data on the light; length of tubes, type (T5 HO for example, or something else), and the dimensions of the tank (length, width, depth).  What plant species you have is important, as they have differing light needs and thus differing nutrient needs.  Also, the duration each day of the tank light as this also factors in.  Plants can only photosynthesize (this is how they grow) if they have sufficient light intensity and all required nutrients are available; as soon as something is missing or insufficient, photosynthesis slows and this is when algae has the advantage.
 
I should also ask what the GH (general hardness) of your source water (presumably tap) is, as this is an important source of the "hard" minerals.  You can get this info from the municipal water authority.
 
Byron.

 

OK, now that I've seen the photos and read the data, I will be asking more questions.
 
First, on the light.  Can you perhaps post a link to the data on the light fixture you have, such as the manufacturer's site or something?  I think I have an idea what this is, but would like to see if I can find some output data.  As for the tubes, the 6500K is perfect.  This on its own might be sufficient...can you remove the other tube and will this one tube still light?  Or do both have to be in and on?  Aside from the second tube perhaps not being necessary, it is as you have surmised intended for marine tanks and is certainly part of the problem.  Actinic light is usually detrimental to plants because it can promote algae.  While aquatic plants do need blue light, along with red and green, too much blue and insufficient red to balance can be problematic.
 
Second, on that brownish film on the sword leaves and some of the decor...does it wipe off with your fingertips?  If it does, this is diatoms, but if not, it may be a form of brush algae.  How long has this aquarium been running?
 
The dimensions indicate just over 18 US gallons.  The dimensions relate to the light intensity, so I'll wait until I can hopefully find more data on this lighting.
 
The plants are not that bad.  Flourish Comprehensive is a good complete supplement, I use it myself.  Once a week, sometimes twice...this we will pin down when I have the light sorted out.  As for the Excel, which is a so-called liquid carbon supplement...this is something I will not use or recommend.  If contains glutaraldehyde, a very toxic disinfectant.  Some plants melt when this is used at recommended levels, and if it should be overdosed it can kill plants, bacteria and fish.  It is used in hospitals to disinfect, and in antifreeze and embalming fluid.  I personally do not see a value in adding something like this to a fish tank.  Vallisneria (I suspect this is what you meant by "varisalla") is usually if not always completely killed by Excel if it is used daily as Seachem suggest.
 
An explanation on the plants having larger leaves and now smaller.  This actually is somewhat normal.  Many plants like the swords are marsh or bog plants that can live half the year emersed in boggy soil and half submersed; such plants are cultivated emersed in nurseries because it is easier, less expensive and faster than submersed.  But when submersed, they undergo a change, and the tougher emersed leaves will slowly die off and be replaced by new growth from the centre of the crown which will be the submersed form.  In time these may become as large as the originals, or not, depending upon light and nutrients.  I would leave the old leaves for a time, until they really begin to yellow, as some of the plant nutrients are mobile, and these can be moved by the plant from the older leaves to the newer growth.  Once the stem of the leaf, called the petiole, browns at the base, nutrients are no longer able to move either way so it can be discarded then; I have found this is when the leaf itself begins to develop increasing yellow margins.
 
You didn't give me the GH, but now that I have seen the plants I doubt this is an issue; still, it would help to know, as the level of the hard minerals (calcium, magnesium primarily) is an important aspect of plant cell development, and it is as well to know all the affecting factors when trying to fix things.
 
Last comment for now.  Not all plants will thrive in the same aquarium.  First, there are the differing requirements concerning light intensity and nutrient availability (these two are closely connected).  Providing more light for a few plants that may need it will always be too much light for others, and here again algae takes advantage.  So when we are setting up a low-tech or "natural" method planted tank, we have to find plants with similar needs and then provide for those, and trick algae into staying away.  There will always be algae in a healthy aquarium, it is part of the natural aquatic system, but when we have plants we need to keep the algae in control, and that means finding and maintaining the balance of light intensity/duration with nutrient availability.  It is attainable, and from the photos here I don't foresee much trouble getting there.
 
Byron.

 

Water Report:  page 9 when you scroll down is the data you want.  GH is given as 238 ppm [= 13 dGH], 207 ppm [= 11 dGH] and 126 ppm [= 7 dGH] for the three reservoirs.  I don't know if you get your water from a single reservoir source, or they are mixed.  But these numbers are all high enough to allay any issues over hard minerals, so that is settled.  Other data of use in that chart is the pH, Alkalinity (this is the KH or carbonate hardness) and Total Dissolved Solids.  I won't get into any of these, just wanted to point them out as you may want to know these numbers down the road.
 
To the light.  As I suspected, this is too bright.  Somehow "removing" one of the two dual tubes would solve the issue, and if taping as mentioned in that other thread works, good.  Be careful as tape will heat, and you don't want to start a fire.  I suppose some sort of block below the one tube might be possible, if anyone knows ideas.  Another possible is to find an electrician who can re-wire the fixture so only the one tube lights; electricians are not inexpensive, but maybe you know a friend who is and can help...or the cost of a new light might not be that much, depending where you get it.  You are in the USA so lots of online places.  Just throwing out ideas.
 
Diatoms, that is better, they should lessen and disappear as things settle.
 
Algae of some sort forms on the glass of most any aquarium.  I always run a sponge-type scraper over the inside of the front glass (and sometimes side panels too) during every weekly water change, whether I see any algae or not--and doing this every week I never see it, but if I miss a week I sometimes do see the start, so the preventive approach works best.  This also removes (or keeps in check) the biofilm that forms on all surfaces under water, which attracts bacteria, algae, microscopic life of all sorts; it is good to keep this off the front glass.
 
Plants.  The hair grass is the one that may not work with less light, but the others mentioned should be fine with the one dual tube.  Now, I am surmising this from the minimal information on the tubes, but given the tank size and the power of these tubes, I'm fairly confident that just one of them will be perfect.  Floating plants is a very good idea.  I have floaters in all my tanks, simply because the fish expect a "roof" above them, and will always be more colourful and less stressed with floating plants or overhanging vegetation as they would get in the wild.  Water Sprite is ideal, there is also Water Lettuce, and Frogbit.  These are substantial plants that grow very fast, hence using lots of nutrients and light and thus good to keep algae at bay.  Being floating, they can assimilate CO2 from the air, so they tend to do very well generally speaking.  Some stem plants do well floating.
 
The Flourish Comprehensive once a week should supply sufficient nutrients with the reduced light.  After a few weeks, the plants should respond.  A second dose can be given, midweek, but only if needed; I have caused brush algae more than once by doubling the dose, as an experiment, so I know it can occur.  The goal in all this is to establish the balance and stay with it.
 
Byron.

 

 
You're welcome.  If you really want to get into aquatic gardening, which is very different from someone like myself who has tanks of fish that happen to have live healthy plants in them, then you would be going down a very different path.  And diffused CO2 (not the "liquid", nor yeast method) is basic to this.  I'll stay out of that and confine myself to helping the present situation as that is what you are working with.
 
Keeping plants is in my view simpler than fish, all things considered.  But what many new to the hobby take a while to realize is that this is a very scientific hobby.  As soon as you put a fish or a plant into a container of water, several biological and chemical processes automatically occur, and some others have to be encouraged by the aquarist.  And to maintain the fish or plant, you need to understand these, and understand something of what will happen if you do this or that.  We in this hobby are governed by the science, like it or not.  Most learn--sometimes the hard way--about the nitrifying cycle, because it is scientific fact and there is no way to avoid it; but with the understanding comes avoidance of future related problems.
 
A planted aquarium is all about balance, light and nutrients.  And this balance can be a any number of different levels, largely governed by the light.
 

 
If your water solely comes from the third source, the one with the lowest numbers for GH, then you could say you have soft water.  The water from the second source is moderately hard, and the first source is getting into the "hard" realm.  Of course, these designations are somewhat subjective.  If you have a mix, then you are likely going to have moderately hard water.  Your plants will be fine whichever; Vallisneria does best in harder rather than softer water, but even the soft is not going to cause issues for this plant.  Fish are more impacted by the hardness.
 

 
Assuming you mean using two 6500K dual tubes, this is only asking for more algae problems.  Without CO2 and daily nutrient supplementation, too much light even if it is good plant light is not going to be all used by the plants and algae will increase.
 
I can surmise that my saying light is used by the plants may not make much sense, so I'll try to explain.  Plants need a certain level of light to drive photosynthesis, and this varies from species to species.  Once the light is present, the plants also require 17 specific nutrients.  These are used for many botanical functions within the plant, but photosynthesis cannot occur without them.  With respect to the nutrients themselves, we know that these have to be in something of a balance among them to benefit plants.  It is easy to understand how an insufficiency of one nutrient may be detrimental to the plant, but in many cases so can an excess because these can cause plants to inhibit the uptake of certain other nutrients.  This is why I recommend comprehensive fertilizers; the proportions of nutrients is pretty much what the plants appear to require.
 
Now, if this balance is present, plants will photosynthesize to the max.  But if any essential nutrient is absent, or runs out, then photosynthesis will slow, and eventually may even stop altogether depending upon circumstances.  At this point, the light becomes more than what the plants can use, but this also means the plants are no longer using all of the nutrients.  Algae takes advantage because algae can manage with almost any light and in an imbalance of light/nutrients, whereas higher plants cannot, generally speaking.
 

 
You should siphon out any algae you remove as this is only going to further feed algae because of the release of nutrients.  In severe cases there can also be other problems, such as ammonia and CO2 increasing, which can harm fish.  Cyanobacteria can arise from an excess of dead algae, and that's another problem.  I do the glass cleaning during the water change, so if I do encounter a patch of algae that I scrape off I can remove it.  Now, a little of this is obviously not a problem, but here we are dealing with more than a regular sprinkling of barely-visible algae.
 
Once the light and nutrients are in balance, algae will not increase, and that is the goal.  What is now present will not go away, unless you remove it.

 

 
These are not so easy to find these days, especially for the more unusual tank shapes.  So the way most go at this point is with a glass cover, that sits down on the frame lip, and then the light fixture sits across the frame.  My suggestion for the light itself would be a single T5 tube (which would use an HO type, HO meaning High Output) or a single dual tube like the ones you have.  The majority oif fixtures you will find today are LED, and that takes us into a whole new ballpark, and I can't help you as I've no experience, so others will hopefully be able to if you ask.
 
 Something just occurrerd to me, so I went and measured my 10g and 20g tanks.  The 20g is 16 inches high, yours is 14, so as far as depth penetration you could look at CFL screw-in bulbs in a fixture taking two bulbs.  I have these "old" type incandescent fixtures on my 10g and 20g, and I use GE 6500K 10w bulbs, two in each, and it is good light.  If my 20g which is deeper works with this, your 18g should too.
 

 
 
Yes, that is probably the water changer we all use for small tanks; for larger, you can get a "Python" that hooks directly to the faucet but the siphon/cleaning end is the same thing.  They are all the same basic idea, I'll attach a photo of one brand so you know what we're talking about.  You can poke the large end into the substrate everywhere you can get to.  I never go under wood, rocks, decor.
 

 
 
No less than once every week, and I recommend no less than 1/3 the tank volume, but 1/2 or a bit over is better.  Given your water parameters from earlier, you should have no issues with fluctuating parameters between tank and tap water, so changing more water will be fine.  I have seven tanks from a 10g up to a 115g, and I change about 60% every week without fail.  It is the single most important maintenance on an aquarium.
 
Thanks for the kind words.  After many mistakes over 20+ years, I hope I've learned something. I'll add a photo of my 20g which is now my QT tank for new fish [so the plants are just culls and daughter plants from the main tanks but they work in this QT] to show what is possible with the two CFL 10w daylight bulbs.  This is the least expensive lighting you can get, in both fixtures and the bulbs.

 

 
There you are, that should work fine (the light I'm referring to).
 
No problems for invertebrates with water changes.  The parameters as I said will be very close, so water stability will actually improve with larger changes because this is going to reduce the "pollution" that only a water change can deal with.
 
Byron.

 

I think Byron may have missed this so I will just add that you do not need to worry about having too much oxygen in the tank.

Oxygen will not displace carbon dioxide from the water, on the contrary it is possible to have a lot of O2 and CO2 coexisting dissolved in the water at the same time. This is desirable - lots of O2 for the fish and good bacteria and CO2 for the plants.

The best way to do this is by surface agitation, i.e. having a good ripple on the surface. This allows for gas exchange between the water column and atmosphere, introducing both oxygen and CO2 into the tank. The amount of these gases dissolved in the water will naturally maintain an equilibrium with the amount of gas in the atmosphere via this gas exchange method.

The only time that surface agitation is not a good idea is if you are artificially introducing higher concentrations of gas into the water via a pressurized CO2 system. A high degree of surface movement would simply gas the extra CO2 off to bring it back into equilibrium with the atmosphere. You don't have to worry about this as you're not adding pressurized CO2, so you actually WANT good gas exchange as it will help to improve both O2 and CO2 levels in the tank.